Internet Info 1997 December/Internet_Info_CD-ROM_Walnut_Creek_December_1997.iso/faqs/rec/answers/bicycles-faq/part4

Internet Message Format | 1997-10-01 | 106.9 KB

Path: senator-bedfellow.mit.edu!bloom-beacon.mit.edu!news-out.internetmci.com!newsfeed.internetmci.com!164.67.42.145!nntp.info.ucla.edu!134.139.1.31!csulb.edu!drivel.ics.uci.edu!news.service.uci.edu!draco.acs.uci.edu!iglesias
From: [e-mail] (Mike Iglesias)
Newsgroups: rec.bicycles.misc,news.answers,rec.answers
Subject: Rec.Bicycles Frequently Asked Questions Posting  Part 4/5
Supersedes: <[e-mail]>
Followup-To: rec.bicycles.misc
Date: 30 Sep 1997 16:09:10 GMT
Organization: University of California, Irvine
Lines: 2409
Approved: [e-mail]
Distribution: world
Expires: 30 Oct 97 00:00:00 GMT
Message-ID: <[e-mail]>
References: <[e-mail]>
NNTP-Posting-Host: draco.acs.uci.edu
Originator: [e-mail]
Xref: senator-bedfellow.mit.edu rec.bicycles.misc:84100 news.answers:113439 rec.answers:34360

Archive-name: bicycles-faq/part4

[Note:  The complete FAQ is available via anonymous ftp from
draco.acs.uci.edu (128.200.34.12), in pub/rec.bicycles.]

------------------------------

Subject: 8.42  Cassette or Freewheel Hubs
From: Jobst Brandt <[e-mail]>

All cassette hubs are not nearly alike.  That is apparent from the
outside by their appearance and by the sprockets that fit on them.
More important to their longevity is how their insides are designed.
Among the mainline brands, some are a response not only to the choice
and interchangeability of sprockets but to the problem of broken rear
axles and right rear dropouts.  These failures are caused by bending
loads at the middle of the rear axle that arise from bearing support
that is not at the ends of the axle.  The following diagrams attempt
to categorize the freewheel and hub combination, and two cassette
designs with respect to these loads.

                           |
          H             H  | |
          H             H Io-- |
      /-------------------\   -o\
      O                   O------
   ===X==================wX=========    Axle has weak spot at "w"
      O                   O------           (Freewheel & hub)
      \-------------------/   -o/
          H             H Io-- |
          H             H  | |
                           |


                           |
          H             H  | |
          H             H  | | |
      /------------------\ /----\
      O                  O O----O
   ===X==================XwX====X===    Axle has weak spot at "w"
      O                  O O----O         (Hugi and Campagnolo)
      \------------------/ \----/
          H             H  | | |
          H             H  | |
                           |


                           |
          H             H  | |
          H             H  | | |
      /------------------\/o---o\
      O                   \-----O
   ===X=========================X===    Axle is loaded only at ends
      O                   /-----O          (Shimano and SunTour)
      \------------------/\o---o/
          H             H  | | |
          H             H  | |
                           |

For clarity only three sprocket gear clusters are shown.

Strong cyclists put the greatest load on the axle by the pull of the
chain because there is a 2:1 or greater lever ratio from pedal to
chainwheel.  The freewheel in the first diagram has the greatest
overhung load when in the rightmost sprocket.  The second design has
the greatest bending moment on the axle when in the leftmost sprocket
and the third design is independent (in the first order) of chain
position.  This third design carries its loads on bearings at the ends
of the axle for minimum axle stress while the other two put a large
bending moment on the middle of the axle.

Common freewheel hubs have not only the highest bending stress but the
smallest axle at 10mm diameter with threads that help initiate
cracking.  The second design type generally uses a larger diameter
axle to avoid failure.  However, these axles still have significant
flex that can adversely affect the dropout.

There are other important considerations in selecting a hub.
Among these are:

1.  Durability of the escapement and its angular backlash (t/rev).
2.  Flange spacing, offset, and diameter.
3.  Type of bearings (cone / cartridge) and environmental immunity.
4.  Ease of sprocket replacement and cost.

Currently the best solution for sprocket retention is a splined body
that allows individual sprockets to be slipped on and be secured by an
independent retainer.  Screwing sprockets onto the body is
indefensible, considering the difficulty of removal.  The same goes
for freewheels.  No longer needing to unscrew tight freewheels is
another advantage for cassette hubs.

------------------------------

Subject: 8.43  Cassette or Freewheel Hubs take 2
From: David Keppel <[e-mail]>

People often ask ``should I use a freewheel or a freehub?''  The
answer is usually ``yes.''

The hub is the center of a wheel and is composed of an axle, bolted to
the bike frame, a hub shell or hub body, where the spokes attatch, and
bearings to let the shell rotate around the axle.

Freewheels screw onto threads on the rear hub's shell, and cogs
attatch to the freewheel.  The freewheel's job is to provide a ratchet
between the cogs and the hub shell, so that you can coast.  Freehubs
are similar but combine parts of the freewheel with parts of the hub
shell.  Freehubs are also sometimes called ``cassettes''.

The usual problem with rear hubs is that axles bend and break.  This
is because the axle diameter was chosen when single cogs were used and
the hub bearing was positioned close to the frame.  Since then, wider
cog clusters have become the norm, the bearings and frame have moved
further apart and leverage on the axle has increased.  But since the
axle has not gotten any stronger, it now has a tendency to fail.

Cassettes fix the problem by incorporating one hub bearing in to the
freewheel mechanism, so that the bearing is once again outboard and
the axle is carrying its load under less leverage.  Some freewheel hubs
solve the problem by using fatter axles.  Since increasing the axle
diameter dramatically improves axle strength, this is an effective
solution and it is possible to use a fat axle that is aluminum and thus
lighter than a standard skinny (weaker) steel axle.

Neither solution is perfect -- cassette hubs let you use standard
replacement axles, cones, washers, etc., but force you to use cogs and
spacers and whatnot by a particular manufacturer (and possibly
derailleurs and shifters -- e.g. XTR uses 4.9mm cog-to-cog spacing
instead of the normal 5.0mm).  On the other hand, fat axles are
nonstandard as are some other replacement parts.

As an aside, the cassette solution leaves a fairly long unsupported
axle stub on the left side, and this is sometimes a source of more
bending problems.  Fatter axles solve the problem on both sides.

Note also that many cassette systems allow you to remove the cogs using
a lightweight tool and thus give you ready access to the spokes in case
of breakage.  Freewheels attatch with a fine thread (another historical
artifact, I believe) and are thus more difficult to remove on the road,
making spoke replacement harder.

In principle, freehubs have all cogs attatch using the same size and
shape of spline, so, e.g., a 20T cog can be used as both a large cog
for a corncob cluster and as a middle cog for wide-range cluster.
However, Shimano's marketing is just the opposite and is directed at
selling whole clusters, without letting you replace individual cogs.
(Shimano's policy is relevant here since they sell 90+% of such hubs.)
Freewheels have several spline diameters in order to clear the bearings
and ratchet.  Further, small cogs typically screw on to the freewheel
body or special cogs with extra threads.  This introduces stocking
problems and may make it hard to build some cog combinations.

I'm not a fan of freehubs for the simple reason that they lock me in
to one maker's choices about cogs and cog spacing.  For example, I had
a 1988 Shimano 6-speed freehub and by 1991 Shimano had, according to my
local bike store, discontinued 6-speed replacement cogs.  Thus, simply
replacing one worn cog meant upgrading to a 7-speed system, which in
turn requires all new cogs, a new freehub body (lucky me -- for some it
requires a new hub and thus new wheel), and, if I wanted to keep index
shifting, new thumbshifters.  Had this been a freewheel-equipped
bicycle, I could have easily switched to another maker's 6-speed
freewheels.

Fortunately, the market is stablizing, with a growing number of makers
producing hubs and cogs using a spline pattern like the more recent
Shimano 7-speed freehubs.  However, it hasn't settled entirely, yet.

        ;-D oN  ( A hubalaboo )  Pardo

------------------------------

Subject: 8.44  "Sealed" Bearings
From: Jobst Brandt <[e-mail]>

> Has anyone had any major problems with the Shimono XT "sealed" Bottom
> bracket besides me?

This subject comes up often and has been beat around a bit.  There is a
basic misconception about seals.  The seals commonly sold in the bicycle
business are not capable of sealing out water because they were never
designed for that purpose.  These seals are designed to prevent air from
being drawn through the bearing when used in, typically, electric motors
where the motor rotation pumps air that would centrifugally be drawn
through the bearing.  If this were permitted, the lubricant would act as
fly paper and capture all the dust that passes, rendering the lubricant
uselessly contaminated.

Seal practice requires a seal to leak if it is to work.  The seepage
lubricates the interface between shaft and seal and without this small
amount of weeping, the seal lip would burn and develop a gap.  In the
presence of water on the outside, the weeping oil emulsifies and
circulates back under the lip to introduce moisture into the bearing.
This is usually not fatal because it is only a small amount, but the
displaced grease on the lip dries out and leaves the lip unlubricated.

The next time water contacts the interface, it wicks into the gap by
capillary action and begins to fill the bearing.  This is an expected
result for seal manufacturers who live by the rule that no two fluids
can be effectively separated by a single seal lip.  Two oils, for
instance, must have separate seals with a ventilated air gap between
them.  If a seal is to work with only one lip the contained fluid must
be at a higher pressure so that the flow is biased to prevent
circulation.

None of the effective methods are used in the so called 'sealed'
bearings that Phil Wood introduced into bicycling years ago.  His
components failed at least as often as non sealed units and probably
more often because they make field repair difficult.  These are not
liquid seals but merely air dams.

[e-mail]

------------------------------

Subject: 8.45  Installing Cranks
From: Jobst Brandt <[e-mail]>

> My cranks get loose, quite quickly too; over about 10 miles or so
> from being solid to flopping about in the breeze.  Any suggestions?

Your cranks are ruined!  Once ridden in the "floppy" mode, the square
taper in the crank can no longer be secured on the spindle.  Get some
new cranks and properly tighten them after lubricating the tapers.
Proper tightness can be guaranteed only by torque wrench or a skilled
mechanic.  The second of these is less expensive and you might be able
to get a demonstration of what is tight enough.

The admonition to not lubricate the tapers of the crank spindle seems
to find life only on bicycle cranks, of all the machines I have seen.
I have pursued the "dry assembly" instruction by talking to crank
manufacturers and discovered that they apparently had warranty claims
from customers who split their cranks open.  It is easy to prove that
cranks cannot split by over-tightening simply by attempting to do so.
It is not possible to split a major brand crank this way, the bolt
will fail first.

Crank failure from "over-tightening" is caused by the re-tightening of
previously properly installed cranks.  Once installed, a crank always
squirms on its taper, and because the retaining bolt prevents it from
coming off, it elbows itself away from the bolt and up the taper ever
so slightly.  This can be detected by the looseness of the retaining
bolt after the bicycle has been ridden hard.

Grease in this interface does not affect performance, because only the
press fit, not friction, transmits load from crank to spindle.  As any
bicycle mechanic can tell you, crank bolts are often appreciably
looser after use, the left one more so than the right.  This occurs
because the left crank transmits torque and bending simultaneously
while the right crank transmits these forces one at a time.  The right
crank puts no significant torque into the spindle.  Either way, the
looseness occurs because loads make the crank squirm on the spindle
and the only direction it can move is up the taper, the retaining bolt
blocking motion in the other direction.

Regardless, whether grease or no grease is used, in use the spindle
and crank will make metal to metal contact and cause fretting
corrosion for all but the lightest riders.  The purpose of the
lubricant is to give a predictable press fit for a known torque.  If
the spindle is completely dry this cannot be said, and even with
marginal lubrication, some galling may occur on installation.
Lubrication is only used to guarantee a proper press because the
lubricant is displaced from the interface in use.  Taper faces of
spindles show erosion and rouge after substantial use, evidence that
the lubricant was displaced.

"Dust caps" aren't just dust caps but retention for loose bolts.  It
is not that the bolt unscrews but that the crank moves up the taper.
However, once the screw is unloaded it can subsequently unscrew and
fall out if there is no cap.

Because cranks squirm farther up the taper when stressed highly, the
unwitting mechanic believes the screw got loose, rather than that the
crank got tighter.  By pursuing the crank with its every move up the
spindle, ultimately the crank will split.  It is this splitting that
has been incorrectly diagnosed as being caused by lubrication.  I have
never seen a warning against re-tightening cranks after having been
installed with a proper press fit.  It is here where the warning
belongs, not with lubrication.

For the press fit to work properly, the pressure must be great enough
to prevent elastic separation between the crank and spindle under
torque, bending, and shear loads.  This means that no gap between
crank and spindle should open when pedaling forcefully.  Friction
has no effect on the transmission of torque because the crank creeps
into a position of equilibrium on the spindle in a few hard strokes.

Failure of this interface occurs when the press fit is too loose
allowing a gap open between spindle and crank.  Torque is transmitted
by the entire face of the press fit, both the leading edge whose
contact pressure increases and the trailing edge whose contact
pressure decreases.  If lift-off occurs, the entire force bears only
on the leading edge and plastic failure ensues (loose crank syndrome).
Tightening the retaining screw afterward cannot re-establish a square
hole in the crank because the retaining screw will break before the
spindle can exert sufficient stress to reshape the bore.  Beyond that,
the crank would split before any plastic deformation could occur even
if the screw were sufficiently strong.

Because retaining screws could become entirely lose from squirming
action, especially if the press is relatively light, "dust caps"
should be used to prevent screws from subsequently unscrewing and
causing crank bore failure.  Besides, the loss of the screw won't be
noticed until the crank comes off, long after the screw fell out.

The argument that the greased spindle will enlarge the hole of the
crank and ultimately reduce chainwheel clearance is also specious,
because the crank does not operate in the plastic stress level.  At
the elastic limit it would break at the attachment knuckle in a short
time from metal fatigue, that occurs rapidly at the yield stress.  In
fact, the depth of engagement (hole enlargement) can increase with an
unlubricated fit faster than with a lubricated one, because
installation friction is the only mechanism that reams the hole.

Jobst Brandt      <[e-mail]>

------------------------------

Subject: 8.46  Stress Relieving Spokes
From: Jobst Brandt <[e-mail]>

> I wonder if "stress-relieving" is entirely correct?  I see it as a
> yielding/hardening process, in which the yield load is increased by
> embedding the spoke elbow in the hub, bending the elbow to a different
> angle, etc.  When unloaded from a high load, this area of the spoke
> should be more or less elastic.

> So I think the term should be "overloading" or "hardening" -- any
> thoughts??

Yes.  I am certain that the concept of stress relieving is obscure to many
if not most people because after seeming to understand it, comments like
this one surface.

A spoke is cold formed from wire that is (at least DT) as hard and
work hardened as it will get.  The process after tensioning a wheel
does not further harden the spokes.  The wire is straightened by
running it through staggered rollers in X and Y directions.  The
rollers have, like a degausser, ever diminishing excursions.  This
gets rid of the natural curl left from being shipped in a coil.  If
the wire was not curled before winding it would be a dangerous weapon
on the spool because if the end got loose, all hell would break loose,
making a huge birds nest.

Anyway, the straightening process leaves the spoke with internal
stresses that are well balanced and relatively low.  I haven't given
this a lot of thought but it seems that if there were a large number
of rollers, the stress might approach zero.  After this process, the
spoke gets its head forged on is cut to length, threaded and, and
lastly its head is crudely but accurately knocked to one side to
produce the elbow.

The threads, head, and elbow, contain metal that went beyond yield as
well as metal that did not.  The metal in these zones is stressed one
part against another, one wanting to return to the condition before or
during forming, and the other to the formed shape.  On lacing the
spokes into a wheel, the elbow is additionally bent (brought to yield)
and upon tensioning this stress remains at or reaches the yield point
it if it wasn't already there.  The threads, that have locked in
stresses (all stresses are ultimately tension and compression) is
selectively stressed at the contact points with the nipple thread and
in tension in the core that already was in tension because thread
rolling stretches this portion of the spoke slightly.

The result is that a freshly built wheel has spokes locations where
stress is guaranteed to be at the yield point.  If used this way, the
cyclic load with each wheel revolution will cause spokes to fail in
fatigue at these high stress points.  The load on the wheel only
unloads spokes but because the spoke is operating up to the yield
point, it cannot withstand many stress cycles.  The greater the load
(unloading) the sooner it will fail because when operating close to
the yield stress a metal cannot survive.  Only the lightest riders who
ride smooth roads might not experience failures.

The purpose of stress relieving is to relax these high stress points
in the spokes.  The purpose is not to bed the spokes into the hub.
Bedding in has usually already occurred sufficiently for practical
purposes during tensioning.  By stretching each spoke with a strong
grasp, its tension can be temporarily increased by 50 to 100%.
Because a spoke operates at about 1/3 its yield stress, this operation
has little to no effect on the spoke as a whole.  Stress relieving
affects only the microscopic zones of the spoke that are at high
stress (near or at the yield stress).  By stretching these zones and
relaxing the load afterward, the margin to yield is as much as the
overload or more.

A whimpy grasp of the spokes during stress relieving is close to
worthless and dropping the wheel, bending it in a partially opened
drawer, pressing on the rim with the hub on the floor and the like is
as close to useless as you can get.  The only method that I have seen,
but do not recommend, is walking on the wheel while wearing tennis
shoes and carefully stepping on each pair of crossed spokes.  The problem
with this is that it bends the rim and it is difficult to be sure each
spoke gets a good stretch.

IT IS STRESS RELIEVING!  At least that's what I am referring to by the
term.

Jobst Brandt      <[e-mail]>

------------------------------

Subject: 8.47  Traffic detector loops
From: Bob Shanteau <[e-mail]>

A traffic loop detects metal objects such as cars and bicycles based on
the change in inductance that they induce in the loop. The loop is an
inductor in an LC circuit that is tuned to resonate at a certain
frequency. A metal plate over the loop (like a car) causes the magnetic
flux to be shorted, reducing the inductance of the loop. This causes a
change in resonant frequency, which is detected and sent to the signal
controller. One of the ways of testing a loop is to create a loop about
2 feet in diameter with several turns of wire (connecting the ends) and
placing the test wire in the middle of the traffic loop. The test wire
should cause a dectection, if all is working.

The same effect is seen with a vertical piece of metal, such as a
bicycle, but is weaker. Because aluminum conducts electricity quite
well, aluminum rims help. Steel rims are OK. Non-metal rims cannot be
picked up at all. A bicycle with aluminum rims will cause about 1/100
the change in inductance of a car.

It is always possible to set a detector's sensitivity to pick up a
bicycle. The trade-off is in longer detection times and the possibility
of false detections from vehicles in adjacent lanes. Most people who set
signal detectors use the lowest sensitivity setting that will pick up
cars reliably.

I advocate using the highest setting that will avoid picking up vehicles
in adjacent lanes. Digital circuits used in modern detectors can use
high sensitivity settings without unacceptable increases in detection
times. Unfortunately, there are still a lot of old detectors out there,
and most people who work on signals use principles based on the
performance characteristics of old detectors.

In any case, bicyclists should, as a general rule, place their wheels
over one of the slots to maximize their chance of being detected. That
is where the magnetic field perpindicular to the wheels is strongest.
Bouncing the bike or moving it back and forth does no good. If you have
a metal frame, another tactic that may work is to lay the bicycle down
horizontally inside the loop until the light turns green.

Advancements are under way that may make traffic loops obsolete some
day. In particular, radar, infrared and sound detectors have been
introduced. Systems based on video cameras are especially promising.
Such systems can easily detect bicycles. Such a system may even be able
to detect pedestrians some day.

Bob Shanteau, PhD. PE
Registered Traffic Engineer

------------------------------

Subject: 8.48  Gluing Sew-up Tires
From: Roger Marquis <[e-mail]>

[More up to date copies of Roger's articles can be found at
 http://www.roble.com/marquis/]

 Davis criterium, it's hot, hot, hot.  The pace is fast and the
corners sharp.  Inevitably some riders are going to roll tires,
happens every year.  What can you do to insure that your sew-up
tires stay glued when the mercury rises?

There is no one cause of poor tire-rim adhesion so let's start at
the beginning, new rims and tires.  Most rims are shipped with a
coating of anti-corrosive substances that closely resemble grease.
This has to be thoroughly removed with solvent and a clean rag
before you can put down the first coat of glue.  Fast Tack is not
the best glue to use on a bare rim.  Instead try Clement, Wolber or
one of the other slower drying glues.  Put a thin coat of glue all
the way around and leave the wheel(s) to dry for at least 12 hours.

 While this glue is drying you might check your tires for any latex
that might be covering the base tape.  If there is any latex at all
give it a good roughing up with coarse sandpaper before coating it
with a thin layer of standard glue or Fast Tack.  This too should
be left to dry for a few hours.  If you're a light rider or don't
plan on doing any hard cornering on hot days you can usually leave
out this step but always roughen the latex on the base tape.

 After the base coat of glue has dried it's time for the adhesive
layer.  This should be thicker than the first layer but not so
thick that it can squeeze out from under the tire when you mount it
and get on the rim and sidewalls.  If you are using a traditional
style road glue let it dry for ten to fifteen minutes before
putting your tires on.  Tires should be mounted on Fast Tacked rims
immediately.

 New tires usually need a good stretching before they will go onto
the rim without tending to roll and get glue all over them.  I
usually stretch a tire by pulling it around my knees and feet for
a few seconds and then mounting it on an old rim for a while.  You
might want to try mounting the tire on a dry rim first to see just
how much stretching it will need.

 If you used traditional sew-up glue you should wait at least 12
hours before doing any serious cornering.  If you need to race
right away you can use Fast Tack and corner confidently within an
hour.  Be sure to spread the glue evenly over the surface of the
rim using your finger or a brush.  To get the last section of tire
onto the rim without making a mess grab the remaining 3 or 4 inches
and lift the tire away from and over the rim.  This can be
difficult if you forget to stretch it beforehand.

 Some glues work better than others in hot weather.  Fast Tack works
best followed by Wolber and Vittoria with Clement in the middle and
Tubasti at the bottom of the list.

 When buying Fast Tack be sure you get the real thing.  3-M sells
other trim adhesives in boxes nearly identical to Fast Tack.  These
trim adhesives do not work for bicycle tires!  Be careful that
whatever glue you do use has not separated in its tube.  If it has,
take a spoke and stir it up before you squeeze it out.  I have also
heard of mixing different glues before application.  This is a
dangerous shortcut that yields unpredictable results.  Fast Tack
and Clement are the most popular tire adhesives.  Even though Fast
Tack will dry out you can get a few tire changes between
replications if you have a good layer of traditional glue on the
rim underneath it.  Racing tires though, should be reglued each
time.  Base tapes can come apart from the tire in hot weather and
underinflation can cause tires to roll as well.  Check these things
as well as the tread for wear or cuts before every race and you'll
be able to descend and corner with confidence.

Roger Marquis ([e-mail])

------------------------------

Subject: 8.49  Common Torque Values
From: Mike Iglesias <[e-mail]>

These torque values are from the Third Hand catalog.  All values are in
inch pounds (in lbs); to convert to foot pounds (ft lbs), divide by 12.

Stem binder bolt              100-120   Brake levers to handlebars    75-95
Handlebar binder              145-200   Brake cable binders           55-75
Controls to frame              35-45    Straddle nut (yoke)           50-70
Front shifter to frame         25-45    Brake pads to brake           45-75
Front shifter to cable binder  25-45    Brake dome nut                50-80
Rear shifter to frame         120-145   Crank bolt                   250-300
Rear shifter cable binder      25-45    Chainring bolts              100-120
Jockey wheel bolt              25-45    Nutted front hub               180
Seat binder bolt               35-55    Nutted rear hub                300
Caliper brakes to frame       100-120   Waterbottle cage              25-35
Cantilever brake to frame      45-60    Fender to frame bolts         50-60
Cantilever brake link wire     35-45    Toeclips to pedals            25-45
Kickstand                       60

------------------------------

Subject: 8.50  Measuring the circumference of a wheel
From: Jobst Brandt <[e-mail]>

For accuracy, the speedometer wants to know how far the bicycle
travels per wheel revolution (under normal load and inflation).
Therefore, that is what must be measured, and it is commonly called
the "rollout distance".  To make this measurement, sit on the bicycle
in typical riding position next to a wall for support, and roll
forward, starting with the valve stem exactly at the bottom at a mark
on the floor.  When the stem is again exactly at the bottom, measure
the distance traveled.  Typically this distance, for a 700-28 tire at
120 lbs pressure, can be as much as 30 mm shorter under load than
rolling the unloaded wheel for one revolution.

------------------------------

Subject: 8.51  Tubular Fables
From: Jobst Brandt <[e-mail]>

> Why is it better to deflate tubulars between rides or is this just a
> silly rumor?

Yes and no.  The "rumor" arises from a misunderstanding.  Track tires,
and these are most often still tubulars, are generally inflated to
more than 10 bar and are dangerous if they were to explode.  Good
track tires, unlike road tires, are often made of silk with fine and
thin strands that are not coated or otherwise protected.

I have seen these tires get touched by another rider's pedal and
explode, or even when carelessly laid on any angular object, they can
burst because only breaking a few cords is enough to start a burst.
For this reason track tires are best deflated to less than half their
running pressure when not in use.  I can still vividly hear the sound
of a tire exploding in an indoor track although I heard it only a few
times years ago.  It is not something you would like to have happen in
your car or room.

The reasons people give for deflating tubulars are generally false and
are given for lack of understanding.  This is what makes it sound like
an old wive's tale.  Most people do it just to be doing what they
think is "professional" when in fact the protected sidewalls and
pressure of road tubulars makes deflation as meaningless for them as
it is for clinchers.

------------------------------

Subject: 8.52  Folding a Tubular Tire
From: [e-mail] (Jobst Brandt)
Date:    Thu, 08 Aug 1996 15:31:33 PDT

Although there are many arcane folds that people devise, it boils down
to pragmatism.  Most spares are used tubulars because those who use
them typically ride together and for a new rider someone offers a
spare that gets returned or not at some later time.  Therefore, we are
talking about a previously glued tubular and the point is to prevent
the whole tire from getting goo all over the tread and sidewalls, so
you flatten the tire against itself lengthwise with the sticky base
tape stuck to the sticky base tape.  Now you have about a 40 inch long
flat tire that when folded in half twice makes the typical wad that
riders carry under their saddles secured by a footstrap.

Footstraps being nearly extinct, I don't know what people use today,
but whatever it is, it must be tight and secure.  If it isn't, the
tire will jiggle enough to abrade the sidewalls to become a
pre-packaged blowout, to be installed when you get a flat on the road.
Don't do it.  Most spare bags sold today are not good places to put a
tubular tire because they will allow the tire to vibrate too much.

It's bad news to ride alone with one spare anyway, so you ought to
ride with other tubular riders when you go any significant distance
from appropriate tire service.  It's not like carrying a tube and
patch kit that can go until you run out of patches (you can cut
patches in half too).  The advantage of using tubulars is so marginal
that the little weight saved is best applied to track and criterium
racing where its minuscule reduction in rotational inertia can at
least be argued to have some significance.

------------------------------

Subject: 8.53  Frames "going soft"
From: [e-mail] (Jobst Brandt)
Date:    Thu, 27 Mar 1997 16:29:15 PST

> I have read accounts of "frames going dead" in cycling literature in
> the past.  If you have information that debunks this, I'd like to
> know about it.  The explanations I have read claim that the flexing
> of a metal causes it to heat up and harden, making it more brittle.
> Eventually it will break under stress.  In fact, I read recently
> that aluminum frames are coming out with warning stickers stating
> "this frame will break someday".  I have also read that this happens
> to titanium and steel.

It was in print, therefore it is true!  Also known, is that a freshly
washed and polished car runs better.  Just the idea that the car is
admirably clean makes this concept appear true for many drivers.  The
same psychosomatic mechanism is at work when a bicycle racer thinks it
is time for a new frame.  I even suspect that some frame builders
assisted in spreading this idea to improve frame sales.

Metal fatigue and failure occur, but they do not change the elastic
response of the metal.  Steel (and of course aluminum and other common
metals) have been metallurgically characterized over more than a
century to a precise understanding.  None of this research has shown
the possibility of perceptible change in elastic response from any
stresses to which a bicycle frame might be subjected.

You mention brittleness.  Brittleness is not a perceptible
characteristic unless the metal breaks.  Hardness is also not
perceptible unless you exceed the elastic limit and permanently bend
the frame to experience its yield point.  What escapes the purveyors
of the "softening" or for that matter "hardening" effect, is that
neither of these effects alter the elastic modulus of the metal.

A coat hanger and a highspeed steel drill of the same diameter have
the same elastic bending stiffness.  For small bending deflections,
both are equally stiff, although one can bend farther than the other
and still spring back unchanged.  The stress at which it permanently
deforms is the measure of hardness of the metal, not its elasticity.

The other dodge is that the frame is brittle and may have cracks.
Brittleness is a description of the failure mode, not its elastic
response.  It means the metal does not take a set but breaks at the
elastic limit.  If not, it springs back unchanged as do many ceramics.
This occurs when a dish or glass is dropped and does not break.  It is
not bent and none of the shards show any distortion.  It either breaks
or it doesn't.  That's brittleness personified.

Classically, bicycles have parts or frame failures in which the rider
says he didn't notice anything before failure.  This is true for
cranks and sometimes frames.  The reason for this, is that to permit
any perceptible change in deflection, all the added elasticity must
come from a crack that has practically no volume.  So the crack would
need to open substantially to, by itself, allow perceptible motion.
Since this is not possible without complete failure, the crack grows
in length, but not width, until the remaining cross section can no
longer support the load, at which time it separates.

> If these ideas have been widely disproven, I'd appreciate knowing
> how.  I've read all six parts of the FAQ and did not see it mentioned.

The reason this was not in the FAQ may be that the whole subject is so
preposterous to engineers, metallurgists, and physicists, that they,
the people who might explain it, are generally not inclined to bother
discussing whether "the moon is made of green cheese" or not.

> PS. If what you're objecting to is the use of the word "dead" as
> opposed to brittle and inflexible, I'll grant you that.

The objection is that you present something for which there is no iota
of scientific evidence, nor any even slightly credible explanation, as
though it were fact.  It is as though bicyclists have a different
natural world, where the technical laws are entirely different from
all other machinery, and the most perceptive technical insights come
from the strongest bicycle racers.  "After all who knows more about
bicycles, you or the world champion?" is a common retort.

Jobst Brandt      <[e-mail]>

------------------------------

Subject: 8.54  Inspecting your bike for potential failures
From: [e-mail] (Keith Bontrager)

Handlebars are probably the one component that deserves the most
respect.  Easton recommends a new bar every two years.  I don;t recall
if they include an "if you race" preface.  I'd say that's probably
about right.  Same for our aluminum bars.  Yearly would be good
on bars that have not been engineered for extended fatigue lives.

Of course, if you don;t race, if you have more than one bike, if
you are a smooth rider, if you like to do "skyshots" you need to
work this in to the estimate.  Getting tougher, eh?  Many people
could ride on the good quality bars into the next millenium without
a problem.  How do you sort it out?  I don't know.

Many parts (not bars or forks) will give you ample warning if you bother
to inspect your bike regularly.  Clean it.  Look at it.  There
are "hot spots" all over the bike that deserve carefull attention.

Fork crown.  Welds if a rigid fork, crown material if its a sus fork.

Steerer.  Hard to look at, but once a year, especially if it's aluminum
or if you've crashed hard with a big front impact.  Also if there are
noises from the front of the bike when you climb or sprint, or
if the bike starts handling funny.  Be careful when you change lower
head set races so you don't gouge up the steerer at the bottom.

If you have an AHS stem/steerer look at the steerer at the point
where the stem and HS bearings meet.  Critical!

Stem.  All of the welds and the binder.  Especially if you are
a 200lb sprint specialist.

Down tube/head tube joint of the frame - underneath.

Top tube/ head tube joint - same location.

Seat tube - near the BB shell and near the seat binder clamp slot.

BB spindle.  Hard to look at, but once a year.  Look near the tapers
where the crank fits on.  This is the weak spot.  If the crank
feels funny when you are pedaling (hard to describe the feeling)
or if it comes loose unexpectedly, look long and hard at the spindle.
Cartridge BBs that allow you to change the bearings should be
treated with some respect.  You can keep fresh bearings in them
forever, guaranteeing that they'll be in service until the
spindle fails!

Cranks.  Check the right hand arm all around where the arm leaves
the spider.  Also check the hub where the arm attaches to the
spindle - especially if the arm is machined from bar (CNC).  The
section near the pedal threads was prone to failure on older
road cranks though I have not seen this on MTB cranks (yet!).
Look all over the arms on the light aftermarket cranks.  Often.
Twice.

Seat post.  Pull it out and sight down the quill.  Any ripples
or deformation around the area where the post is clamped in the
frame indicates a failure on the way.  The clamps are too varied to
comment on.  If you have to run the fasteners real tight to keep
the saddle from slipping you should put new, very high strength
fasteners in every year or so.  The clamps can come loose from the
quill tube sometimes (ask me how I know).  Grab the saddle and give it
a twist.

Saddle.  Rails near the seat post support pieces.

Rims.  material around spoke holes can pull out, side walls can
wear through, side walls can fail due to extrusion defects.  Some
of these are hard to see.

Frames around the dropouts (not a problem with newer frames as it
was with older campy forged drops).  Chainstays near the CS bridge
and BB shell.

Hubs.  Flanges can pull away from the hub body.  Not a problem
in most cases unless the wheels are poorly built, you are running
radial spokes and ride real hard, have poorly designed aftermarket
hubs, or are very unlucky.

Many components will make a bit of noise or make the bike feel funny
before they go.  Not all will.  Respect this.

------------------------------

Subject: 8.55  ETRTO numbers for tire sizes
From: Osman Isvan <[e-mail] >

There is nothing wrong with tire/rim compatibility. If
we...stop calling them with colloquial names such as "26 inch
wheel", "road wheel", etc., we would be all set.

There is no dimension on a mountain bike rim that is even
close to 26 inches. The ETRTO number, bead diameter in
millimeters, is *molded* on the sidewall of the tire (to make
mislabeling almost impossible) and if it matches, it will
match. There is nothing confusing, mysterious or misleading or
complicated about the ETRTO designation. The ETRTO designation
also includes the width of the tire to be sure it is not too
narrow or too wide for the rim, but this dimension is not
accurate as it is not critical.

Common standard bead diameters are 559 mm (ATB), 571 mm
(Triathlon) and 622 mm (road). They are a reasonable size
smaller/larger than each other, so what's the problem?

The confusion comes from us (marketers and consumers)
referring to both the 559 and the 571 standards, and a slew of
others, as 26" for some reason. The term "26 inch wheel"
refers to the approximate outside diameter of the inflated
tire, and has nothing to do with tire/rim compatibility...

This is no different with cars, but in automotive "lingo" the
colloquial names for wheel sizes are the rim diameter (and
that's what matters for compatibility), not the tire outside
diameter. The same car comes with either "13 inch" or "14
inch" wheel options but the outside diameter of the tire may
be the same. The rubber part takes up the difference.
Motorists refer to their RIM SIZE when they talk about wheel
diameter. A 13 inch tire such as "175/70 R 13" means it will
fit to a 13 inch rim.

We should do the same. It is possible to build the same
outside diameter by either using a 26 mm wide tire and 559 mm
(mountain) rim (ETRTO 26-559) or a 20 mm wide tire on a 571mm
(triathlon) rim (ETRTO 20-571), and this doesn't imply they
would be interchangeable. And because the 559 mm (Mountain)
rims have a diameter of only 22 inches, it takes very fat 2.0
inch (Mountain) tires to bump them up to 26". Of course they
wouldn't accept skinny triathlon tires of same thread
diameter.

When ordering tires, order according to bead diameter (ETRTO
designation). This will solve any problems with compatibility.
If the salesperson doesn't understand, ask to look for the
number which is molded with the casing.

------------------------------

Subject: 8.56  Using a Quick Release
From Mark Irving <[e-mail]>

The odd-looking thing which attaches most front wheels, many rear wheels
and some seatpins is not a sort of wingnut.  It is a quick release lever.
If it is not properly fastened, your wheels are loose.  If this description
isn't clear, go to any bike shop or find any local bikie person and get
them to show you.  It's hard to describe, not obvious until you've done it
yourself, and it is important to get right.  It's easy when you know how --
road racers can get their wheels changed in five seconds!

1.  Make sure the floppy lever is pushed over to its "OPEN" side. This
lever operates a cam to close up the 'skewer' later.

2.  Loosen off the little nut on the other end of the skewer just enough to
get the wheel into the dropouts in the frame.  Slide the wheel into the
frame, and balance it there while you do the next bits.

3.  With one hand, hold the operating lever straight out (parallel to the
axle), halfway between OPEN and CLOSED.  With the other hand, tighten the
nut opposite until you feel resistance.

4.  Push the operating lever over to CLOSED.  This should be a tough
operation, if you've got the nut adjusted right.  It should not hurt, but
it should leave a dent in the palm of your hand for ten to twenty seconds
afterwards!  If you have the tension right, the wheel is now very safely
and solidly held.

5.  If the lever really won't close all the way, open it (the full 180
degrees to OPEN), loosen the nut about 1/4 turn, and go back to step 4.  If
it closes all the way without much resistance, open it all the way, tighten
the nut 1/4 turn, and go back to step 4.

If your bike doesn't have the stupid bumps, clips and 'lawyer lips' often
added, you'll never need to adjust the nut again.  The only action needed
is to flip the lever between CLOSED and OPEN.

The subtle extra is to point the Q-R lever down, towards the ground, in its
CLOSED position, so that it doesn't get caught on anything solid when
you're riding.  This is infinitely less important than doing it up
properly.

------------------------------

Subject: 8.57  Tube and Tire Casing Repair
From: John Forester <[e-mail]>

  There sure seems a dearth of knowledge about patching both tubes and
casings.

  Yes, the idea that tubes could be patched without liquid cement was a
good idea, but only as an idea to research to see whether an adequate
adhesive could be developed. So far as I know, all the peel and stick
adhesives are very viscous liquids. That means that they don't harden and
therefore that the air pressure will slowly leak into and through them. If
the viscosity is high enough it will take the air under pressure a long
time to form another leak. A glueless patch of the peel and stick variety
cannot have effective solvents in it, because the solvent would evaporate
during storage. Even if the patch were sealed inside a container that
prevented the evaporation of the solvent, the system would have the problem
of getting enough glue onto the tube and then letting the solvent partially
evaporate from the open joint for the joint to be made. You might as well
use the old system.

The problem that some experience is that they find the cement hardened in
the zinc dispensing tube. The answer to that is to buy the cement and its
solvent in bulk and carry a small quantity in a small jar with a screw cap.
A metal jar would be most useful, but I do not know of any common source for
such. Small glass jars are commonly available and last well enough.
Periodically, examine the cement inside and top up with solvent if it gets
too thick. Because the cement tends to glue the cap to the jar, it is
desirable to wrap both the jar and the cap with several layers of adhesive
tape to provide a better gripping surface at a larger radius.

Two kinds of cement are available. The traditional cement is rubber cement,
Camel #12-086 Universal Cement, available at tire shops. The other cement is
contact cement, available from hardware stores.  While the modern
formulations often are non-flammable and use chlorinated hydrocarbons as
solvents, buy the flammable kind, if available, because the chlorinated
hydrocarbons are detrimental to rubber. (Very important for diluting rim
cement for tubular tires. Not so important for just tire patches or boots
because the solvent evaporates.) In any case, use toluol as the replacement
solvent, available at hardware stores.

The tube must be cleaned before applying the cement. Stick medium sandpaper
to tongue depressors and cut to lengths that fit your patch kit.

  Cut casings are repaired with an internal boot. Satisfactory boots are
made from cotton trouser fabric or from lightweight dacron sail fabric.
These must be cemented by contact cement, not tube cement. Cut pieces of
suitable size, so that they run almost from bead to bead when laid inside
the casing. Coat one side with several layers of contact cement and let it
dry completely before storage. Before applying, coat the inside of
the casing with contact cement and press the boot into place before the
cement dries. Wait about ten minutes before inflating the tire. If you wait
too long, the cement really hardens and there will be a narrow spot in the
casing because of the greater strength where the patch reinforces the
casing.

  It is probably possible to use contact cement as the tube patch cement.
Do not use tube cement for boots; it slowly creeps and allows the boot to
bulge. So carry a small jar of each cement, or one of contact cement.

  Contact cement is suitable for closing the outside of the cut also, but
it must be applied in several layers and allowed to dry thoroughly before
use, or it will pick up particles from the road. Duro Plastic Rubber is a
thicker black rubber paste that can be applied in one layer and left to
harden.

------------------------------

Subject: 8.58  The Continuously Variable Transmission
From: Jobst Brandt <[e-mail]>

The Continuously Variable Transmission (CVT) is the holy grail of many
inventors who are not convinced that it is an impossibility.  That is
to say, the positive engagement, continuously variable transmission,
that does not rely on friction, electrical, or hydraulic ratios but
uses mechanical gearing, is not possible.

The CVT does not exist, and I am convinced it will not.  If it were
possible, railway locomotives, trucks, buses, and cars would long ago
have used them.  Strangely, it is in bicycling that the strongest
believers of the concept reside... as if there were more money to be
made in bicycles or some such notion.  In fact, the bicycle with its
enormously adaptable human motor doesn't need a CVT.  In addition, its
low input speed and extremely high torque, make the bicycle one of the
most difficult vehicles to equip with gearing.  For this reason it
uses derailleur chain drive, that is found practically nowhere else.

------------------------------

Subject: 8.59  Patching Tubes
From: Jobst Brandt <[e-mail]>

The question often arises whether tubes can be practically and safely
patched.  I suppose the question comes up because some people have had
leaky patches or they consider it an arcane exercise.  Either way, it
need not be difficult if simple rules are followed.

Mold release

Tubes are made in metal molds to which they would stick if mold
release were not sprayed into the mold.  The release agent is designed
to prevent adhesion and it will do the same for patches because it
remains on and in the surface of the tube.  To make a patch stick,
this material must be removed.  That means, the sand paper in the
patch kit is not to roughen the surface but to remove it.  Not
removing the 'skin' of the tube is a major reason for leaky patches.

Once the mold release has been removed, rubber solution can be applied
with the finger by wiping a thin film over the entire area that the
patch is to cover.  After the glue has dried so that no liquid or
jelly remains, leaving the area with a tacky sheen, the patch should
be pressed into place.  Patches can be made from tube material but
this must be done carefully following the same procedure as preparing
the tube.  The trouble is that butyl tube material, unlike patches, is
impervious to rubber cement solvents and will never cure if the glue
is not completely dry.  This presents a substantial problem.

Patches

Patches commonly have a metal foil cover on their sticky side and a
cellophane or impervious paper cover on the other.  The foil should be
pulled off to expose the adhesion surface and the patch pressed into
place.  The backing paper or cellophane often has perforations that
will break if the tube and patch are stretched.  This makes peeling
the cover from inside to outside of the patch possible and prevents
peeling a newly installed patch from its position.

REMA patches, the most commonly available in north American bicycle
shops, have a peculiarity that not all have.  Their black center
section exudes a brown gas that discolors light colored tire casings
in daylight.  This causes the brown blotches often seen on sidewalls
of light colored tires.

Leaky Patches

Assuming the patch was properly installed, it will still possibly leak
after a few miles, if used immediately after patching.  Because the
tube is generally smaller than the space inside the tire, to prevent
wrinkles on installation, it will stretch when inflated as does the
patch.  Although it stretches less than the rest of the tube by the
greater thickness, it resists stretch more than the tube alone.  Under
the patch, the stretched tube tends to shrink away from the patch, and
because there is no holding force from inflation pressure at the hole,
the tube can peel away from the patch that is held by air pressure.

If the puncture is a 'snake bite', the chances of a leak are even
greater.  Pinch flats from insufficient inflation or overload are
called snake bites because they usually causes a pair of holes that
roughly approximate the fang marks of a snake.  These holes are near
the rim where the contour of the tube is nearly a sharp fold.  This
location is especially susceptible to the tube separation at the hole
closest to the rim.

In a rolling tire, the patch and tube flex, shrink, and stretch making
it easier for the tube to separate from a partially cured patch.  To
test how fast patches cure, a patch can be pulled off easily shortly
after application, while it is practically impossible after a day or
so.  For best results, the freshly punctured tube should be patched
and put in reserve, while a reserve tube is installed.  This allows
a new patch more time to cure before it is put into service.

A tube can be folded into as small a package as when it was new and
practically airless, by sucking the air out while carefully using the
finger opposite the stem to prevent re-inflation.  This is not done by
inhaling but by puckering the cheeks.  Although the powders inside the
tube are not poisonous in the mouth, they are not good for the lungs,
but then that's obvious.

Minutia

The difficult part of loose patches is that separation always stops at
the edge of the patch because air pressure prevents further
separation.  The annoying intermittent slow leaks that occur, often
close when the tube is inflated outside a tire, so the offending patch
cannot be found.  Old tubes to be discarded often reveal partial
failures by cutting through the center of patches with shears.

Tires are less flexible at a patch and will wear slightly faster
there, but patches have no effect on dynamic balance since wheels are
so imbalanced that patches have no effect on the heaviest position of
the wheel.  Heat from braking can accelerate separation of a fresh
patch but this generally does not pose a sudden hazard because lifting
patches most often causes only a slow leak.

------------------------------

Subject: 8.60  Shimmy or Speed Wobble
From: Jobst Brandt <[e-mail]>

Shimmy is not related to frame alignment or loose bearings as is often
suggested.  Shimmy arises from the dynamics of forward motion and the
elasticity of the frame, fork, and wheels, and the saddle position.
Both perfectly aligned bicycles and ones with wheels out of plane to
one another shimmy nearly equally well.  The same is true for bearing
adjustment.  In fact shimmy is more likely with properly adjusted
bearings than loose ones.  The bearing or alignment concept is usually
offered as a cause of shimmy and each airing perpetuates the idea.

Shimmy, the lateral oscillation at the head tube, depends primarily on
the frame and its geometry.  The inflation of the tire and the
gyroscopic effects of the front wheel make it largely speed dependent.
It cannot be fixed by adjustments because it is inherent to the
geometry and elasticity of the components.  The longer the frame and
the higher the saddle, the greater the tendency to shimmy, other
things being equal.  Weight distribution also has no effect on shimmy
although where that weight contacts the frame does.

In contrast to common knowledge, a well aligned frame shimmies more
easily than a crooked one because it rides straight and without bias.
The bias force of a crooked frame impedes shimmy slightly.  Because
many riders never ride no-hands downhill, or at least not in the
critical speed range, they seldom encounter shimmy.  When it occurs
with the hands on the bars it is unusual and especially disconcerting.
There is a preferred speed at which shimmy initiates when coasting
no-hands on a smooth road and it should occur every time when in that
critical speed range.  Although it usually does not initiate at higher
speed, it can.

Pedaling or rough road interferes with shimmy on a bicycle that isn't
highly susceptible.  When coasting, laying one leg against the top
tube is the most common way to inhibit it.  Interestingly, compliant
tread of knobby tires give such high lateral damping that most
bicycles equipped with knobbies do not shimmy.

Shimmy is caused by the gyroscopic force of the front wheel that acts
at 90 degrees to the axis of the steering motion.  The wheel steers to
the left about a vertical axis when it is leaned to the left about a
horizontal axis.  When the wheel leans to the one side, gyroscopic
force steers it toward that side, however, the steering action
immediately reverses the lean of the wheel as the tire contact point
acts on the trail of the fork caster to reverse the steering motion.

The shimmy oscillates at a rate that the rider's mass on the saddle
cannot follow, causing the top and down tubes to act as springs that
store the energy that initiates the return swing.  The shimmy will
stop if the rider unloads the saddle, because the mass of the rider is
the anchor about which the oscillation operates.  Without this anchor
no energy is stored.  The fork and wheels may store some energy,
although it appears the frame acts as the principal spring.

Shimmy can also be initiated with the hands firmly on the bars by
shivering, typically in cold weather.  The frequency of human
shivering is about the same as that of a typical bicycle frame.

------------------------------

Subject: 8.61  Bike Part Failure Web Site
From:    Dave Blake <[e-mail]>

Here it is, the web based rec.bicycles.tech failures compilation at
http://www.keck.ucsf.edu/~dblake/fail.html

This list is provided as a service to anyone interested in which
bike parts are most durable.

The failures are collections of first hand accounts of bike parts
that failed in usage that was not beyond the design of the part.

If you have a bike part that failed on you - send the account
in  ! ! You can view the accounts of others on the web page above.

------------------------------

Subject: 8.62  Rolling resistance of Tires
From:    Jobst Brandt <[e-mail]>
Date:    Thu, 08 Aug 1996 17:17:57 PDT

The question often arises whether a small cross section tire has lower
rolling resistance than a larger one.  The answer, as often, is yes
and no, because unseen factors come into play.  Rolling resistance of
a tire arises almost entirely from flexural rubber losses in the tire
and tube.  Rubber, especially with carbon black, as is commonly used in
tires, is a high loss material.  On the other hand rubber without
carbon black although having lower losses, wears rapidly and has
miserable traction when wet.

Besides the tread, the tube of an inflated tire is so firmly pressed
against the casing that it, in effect, becomes an internal tread.
The tread and the tube together absorb the majority of the energy lost
in the rolling tire while the inter-cord binder (usually rubber) comes
in far behind.  Tread scuffing on the road is even less significant.

Patterned treads measurably increase rolling resistance over slicks,
because the rubber bulges and deforms into tread voids when pressed
against the road.  This effect, tread squirm, is mostly absent with
smooth tires because it cannot be bulge laterally by road contact
because rubber, although elastic, is incompressible.

Small cross section tires experience more deformation than a large
cross section tire and therefore, should have greater rolling
resistance, but they generally do not, because large and small cross
section tires are not identical in other respects.  Large tires nearly
always have thicker tread and often use heavier tubes, besides having
thicker casings.  For these reasons, smaller tire usually have lower
rolling resistance rather than from the smaller contact patch to which
it is often attributed.

These comparative values were measured on various tires over a range
of inflation pressures that were used to determine the response to
inflation.  Cheap heavy tires gave the greatest improvement in rolling
resistance with increased pressure but were never as low as high
performance tires.  High performance tires with thin sidewalls and
high TPI (threads per inch) were low in rolling resistance and
improved little with increasing inflation pressure.

As was mentioned in another item, tubular tires, although having lower
tire losses, performed worse than equivalent clincher tires because
the tubular's rim glue absorbs a constant amount of energy regardless
of inflation pressure.  Only (hard) track glue absolves tubulars of
this deficit and should always be used in timed record events.

------------------------------

Subject: 8.63  Blowouts and Sudden Flats
From:    Jobst Brandt <[e-mail]>
Date:    Mon, 26 Aug 1996 16:58:07 PDT

Bicyclists often report tube failures that they believe occurred
inside the tire casing.  They believe these are caused by a faulty
tube that split or that the rim tape failed.  However, they also heard
a bang after which the tire was flat.  On removing the tire casing
from the rim with tire irons, they discover a burst tube with a large
slash.

If there was an audible bang, then the tire was off the rim.  That the
undamaged tire is still on the rim afterwards proves only that tires
usually fall back into place after exposing the tube.  A tube cannot
blow out inside the tire with a bang, because a bang is caused by a
sudden change in volume, an expansion.  Such an expansion is not
possible within a tire casing.  Beyond that, the resulting clean slash
in the tube cannot occur from rim tape that would cause a gradual
failure along an abraded line that extends beyond the end of the
split.  A burst into a rime hole would cause a starburst hole that is
smaller than the rim socket because the tube shrinks when no longer
inflated.

Tire blow-off occurs most commonly on tandems where substantial energy
of descending mountain roads is converted to heat in rims by braking,
in contrast to a single bicycle, where most of the energy is
dissipated by wind drag.  Rim heating has two effects, of which
increased pressure is probably the lesser one.  Heat softens the bead
of the tire so that it can squirm out of its clinching seat in the
rim.  Tire casing flex at the load point works the tire so that it
squirms out of engagement.  Heat also increases lubricity of the bead
against the rim to facilitate creep.

Short tubes, that must be stretched to fit on the rim, can cause tire
blow-off.  A stretched tube will occupy the space on the bed of the
rim where the tire bead should be to make proper engagement with the
hook of the rim sidewall.  The tube under the bead of the tire can
prevent proper engagement with a hooked rim to cause a blow-off even
without great heat or pressure.

------------------------------

Subject: 8.64  Tied and Soldered Wheels
From: Jobst Brandt <[e-mail]>
Date: Mon, 16 Dec 1996 15:09:03 PST

While writing "the Bicycle Wheel", to conclusively determine what
effect tying and soldering of spoke crossings in a wheel had, I asked
Wheelsmith to loan me an untied pair of standard 36 spoke rear wheels,
on on Campagnolo low and high flange hubs.  I had an inner body of a
freewheel machined with flats so that a wheel could be clamped into
the vise of a Bridgeport milling machine while the left end of its
axle was held in the quill.

With the hub rigidly secured, with its axle vertical, dial gauges were
mounted at four equally spaced locations on the machine bed to measure
rim deflections as a 35lb weight was sequentially hung on the wheel at
these positions.  The deflections were recorded for each location and
averaged for each wheel before and after tying and soldering spokes.

The wheels were also measured for torsional rigidity in the same
fixture, by a wire anchored in the valve hole and wrapped around the
rim so that a 35 lb force could be applied tangential to the rim.
Dial gauges located at two places 90 degrees apart in the quadrant
away from the applied load were used to measure relative rotation
between the wheel and hub.

Upon repeating the measurements after tying and soldering the spokes,
no perceptible change, other than random measurement noise of a few
thousandths of an inch, was detected.  The spokes were tied and
soldered by Wheelsmith who did this as a regular service.  The data
was collected by an engineer who did not know what I expected to find.
I set up the experiment and delivered the wheels.

------------------------------

Subject: 9  Misc

------------------------------

Subject: 9.1  Books and Magazines

  Magazines/Newsletters
  ---------
  Bicycling Magazine, and Bicycling Magazine+Mountain Bike insert
  33 E Minor St
  Emmaus, PA 18098
  [phone]

  Bicycle Guide
  711 Boylston Street
  Boston MA 02116
  617-236-1885

  Mountain Biking
  7950 Deering Avenue
  Canoga Park CA 91304
  818-887-0550

  Mountain Bike Action
  Hi-Torque Publications, Inc.
  10600 Sepulveda Boulevard
  Mission Hills, CA 91345
  818-365-6831

  Velo News
  P.O. Box 53397
  Boulder, CO 80323-3397
  [e-mail]

  Cycling Science
  P.O. Box 1510
  Mount Shasta, California 96067
  [phone]

  Human Power (The Journal of the IHPVA*)
  (* IHPVA == International Human Powered Vehicle Association)
  IHPVA
  PO 51255
  Indianapolis, IN 46251-0255
  [phone]

  OnTour: The Newsletter for Bicycle Tourists
  OnTour Publications
  2113 Arborview
  Ann Arbor, MI 48103.
  Sample issues are only $1, a six-issue subscription only $6

  R.B.C.A./The Recumbent Cyclist
  17650-B6-140th Ave. SE, Suite 341
  Renton, WA 98058 USA

  Tandem Club of America
  Malcolm Boyd & Judy Allison
  19 Lakeside Drive NW
  Medford Lakes, NJ  08550
  Dues are currently $10/year

  Dirt Rag
  5742 Third St.
  Verona, PA
  (412) 795 - 7495
  FAX  (412) 795 - 7439

  Bike Culture Quarterly is an engaging magazine for "[people] who see
  cycling as a way of life rather than an occasional leisure activity".
  It has interviews with people building interesting bikes (Mike Burrows
  about the Obree bike), travel reports, discussions of bicycle
  advocacy, new equipment, and so on.  Its summer issue is the
  "Encycleopedia"  "a personal selection of unorthodox, thoughtful
  cycling products from around the world".

  Price is (British Pounds) 25/year.

  Order by phone  UK:  [phone]   outside UK:  [phone]

  Post:    Open Road
      4 New Street
      York  Y01 2RA,
      England

  They accept Visa, Access, Mastercard, and Eurocard.  Eurocheques are
  also accepted.  From the US, it's easiest to use a credit card.


  Books
  -----
  Bicycling Magazine's Complete Guide to Bicycle Maintenance and Repair
  Rodale Press
  ISBN 0-87857-895-1

  Effective Cycling by John Forester
  MIT Press
  ISBN 0-262-56026-7

  The Bicycle Wheel by Jobst Brandt
  Avocet
  ISBN 0-9607236-6-8) English
  ISBN 0-9607236-4-1) German

  Bicycle Maintenance Manual by Eugene A. Sloan
  (a Fireside book, pub. Simon & Schuster, Inc.)
  ISBN 0-671-42806-3

  Anybody's Bike Book by Tom Cuthbertson

  Bicycles and Tricycles
  An Elementary Treatise on Their Design and Construction
  by Archibald Sharp
  Reprint of the 1896 edition, with a foreword by David Gordon Wilson
  Anytime you hear of a "new" invention for bicycles, look it up in
  here, and you'll find it.
  MIT press  - I have a paperback edition labelled $14.95

  Bicyling Science
  by Frank Rowland Whitt and David Gordon Wilson
  A good book, and an excellent reference.
  Second Edition 1982, MIT press, paper $9.95

  Bicycle Road Racing by Edward Borysewicz

  The Woman Cycist by Elaine Mariolle
  Contemporary Books

  Touring on Two Wheels by Dennis Coello
  Lyons and Berrfard, New York

  The Bicyclist's Sourcebook by Michael Leccese and Arlene Plevin
  Subtitled: "The Ultimate Directory of Cycling Information"
  Woodbine House, Inc.  $16.95
  ISBN 0-933149-41-7

  Colorado Cycling Guide by Jean and Hartley Alley
  Pruett Publishing Company
  Boulder, Colorado

  The Canadian Rockies Bicycling Guide by Gail Helgason and John Dodd
  Lone Pine Publishing,Edmonton, Alberta

  A Women's Guide to Cycling by Susan Weaver

  Favorite Pedal Tours of Northern California by Naomi Bloom
  Fine Edge Productions, Route 2, Box 303, Bishop, CA  93514

  Mountain Biking Near Boston: A Guide to the Best 25 Places to Ride
  by Stuart A. Johnstone, Active Publications (1991), ISBN 0-9627990-4-1

  Mountain Bike: a manual of beginning to advanced technique
  by William Nealy, Menasha Ridge Press, 1992, ISBN 0-89732-114-6

  Greater Washington (DC) Area Bicycle Atlas
  American Youth Travel Shops, 1108 K St, NW  Wash, DC 20005 [phone]
  $12.95

  Bicycle Parking by Ellen Fletcher
  Ellen Fletcher, 777-108 San Antonio Road, Palo Alto, CA 94303-4826
  Cost: $5.95, plus 43 cents tax, plus $3 postage/handling

  Richards' Ultimate Bicycle Book
  Richard Ballantine, Richard Grant (Dorling Kindersley, London, 1992)

------------------------------

Subject: 9.2  Mail Order Addresses

Here's the addresses/phone numbers of some popular cycling mail order
outfits (you can get directory assistance for 800 numbers at
1-800-555-1212 if you don't see the mail order outfit you're looking for
here):

Bicycle Posters and Prints
  P.O. Box 7164
  Hicksville, NY 11802-7164
  Sells bicycle posters and other stuff.


Branford Bike
  orders:  1-800-272-6367
  info:      203-488-0482
  fax:       [phone]


Colorado Cyclist
  orders:  1-800-688-8600
  info:    719 591-4040
  fax:     [phone]

  3970 Bijou Street
  Colorado Springs, CO  80909-9946


Cyclo-Pedia
  [phone]

  P.O. Box 884
  Adrian MI  49221
    Catalog $1 as of 4/91.


Excel Sports International
  orders:  1-800-627-6664
  info:      303-444-6737
  fax:       [phone]

  2045 32nd Street
  Boulder CO  80301


Irvine Bike Source
  [phone] (orders only)
  [phone]
  [phone] (FAX)

  17777 Main St, Unit E
  Irvine, CA 92614


Loose Screws
  [phone]
  [phone] FAX

  12225 HWY 66
  Ashland OR 97520


Nashbar
  orders:  1-800-627-4227  (1-800-NASHBAR)
             216-782-2244  Local and APO/FPO orders
  info:      216-788-6464  Tech. Support
  fax:       [phone]
  WWW:     http://www.nashbar.com/

  4111 Simon Road
  Youngstown, OH 44512-1343


Pedal Phernalia
  Phone:   [phone]

  Box 2566-net
  Ann Arbor MI 48106-2566


Performance Bike Shop
  orders:  1-800-727-2453  (1-800-PBS-BIKE)
             919-933-9113  Foreign orders
  info:      800-727-2433  Customer Support
  fax:
  WWW: http://www.performanceinc.com/PerfBicycle.html

  One Performance Way
  P.O. Box 2741
  Chapel Hill, NC 27514


Schwab Cycles
  orders:  1-800-343-5347
  info:      303-238-0243
  fax:       [phone]

  1565 Pierce St.
  Lakewood, CO  80214


Triathlete Zombies
  (800-999-2215)


The Womyn's Wheel, Inc.
  (Specializes in clothing and equipment for women)
  800-795-7433
  508-240-2437

  P.O. Box 2820
  Orleans MA 02653

------------------------------

Subject: 9.3  Road Gradient Units
From: Jeff Berton <[e-mail]>

The grade of an incline is its vertical rise, in feet, per every 100 horizontal
feet traversed.  (I say "feet" for clarity;  one could use any consistent
length measure.)  Or, if you will accept my picture below,

                                                 *
                                              d  |
                                          a      |
                                      o          | y
                                  R  Theta       |
                              *___)______________|
                                        x
then
      Grade = y/x        (Multiply by 100 to express as a percentage.)
and
      Theta = arctan(y/x)

So a grade of 100% is a 45 degree angle.  A cliff has an infinite grade.

[More from Jobst Brandt <[e-mail]>]

The steepness of a road is generally measured in % grade, which in
mathematical terms is the slope, or TANGENT of the angle, measured
from the horizontal.  This is the ratio of elevation change per
horizontal distance traveled, often called "rise over run".  Typically
a road that rises 1-in-10, is otherwise called 10% grade.

Measuring the distance along the surface of the road instead of
horizontally gives practically the same result for most road
gradients.  The distance along the road surface gives the SINE of the
angle in contrast to the horizontal distance that gives the TANGENT.
For practical purposes the SINE equals the TANGENT for small angles
(up to ten degrees or so).  For instance, a 20% grade (11.3 degrees),
whereas measuring along the road surface gives a 19.6% grade.

The slope of a road is more useful than its angle because it gives a
direct way to assess the effort required to move forward against the
grade, whereas the angle in degrees does not readily reveal this
information.  A 5% grade requires a forward force of approximately 5%
of the vehicle weight (above and beyond the force it takes to travel
similarly on flat ground).  A 15% grade requires a propulsion force of
approximately 15% of the vehicle weight.

Although the angle may be more easily visualized, it does not convert
to effort without a calculator.  For instance a 20% grade is an 11.3
degree angle and is a steep and difficult gradient.  The relationship
between angle and slope is non linear becoming 100% (1:1) at a 45
degree angle.  Likewise, the propulsion force, related to the SINE of
the grade, becomes 70.7% of the weight at 45 degrees.

------------------------------

Subject: 9.4  Helmets

The wearing of helmets is another highly emotional issue that has been
debated many times on rec.bicycles.  On one side, you have the cyclists
who feel that they can do without - the helmet is too hot, uncomfortable,
or they feel they just don't need it.  On the other side, you have
the cyclists who wouldn't be caught riding without a helmet - they like
their head (and brains) they way they are.

Statistics show that three-fourths of the more than 1000 bicycling
deaths each year are caused by head injuries.  Of those killed, half
are school age children.  According to one study, a helmet can reduce
the risk of head injury by 85%.

Consumer Reports did a review of bicycle helmets in the May 1990 issue.
While their report is not what one would see in a cycling magazine,
it does contain some useful and valuable information.  Their tests
showed that no-shell helmets work just as well as hard-shell helmets,
and in fact, the top 9 helmets in their ratings are no-shell models.

There is some controversy about whether no-shell helmets "grab" the
pavement instead of sliding on impact.  If the helmet grabbed, it
might lead to more serious neck or spinal injury.  This topic has
been hotly debated in rec.bicycles, and some studies are in progress
to see if this is true.

There are two standards systems for helmets - ANSI (American National
Standards Institute) and Snell (the Snell Memorial Foundation).  The
Snell tests are more demanding than ANSI, and a Snell-certified helmet
will have a green Snell sticker inside.  Some helmets claim they
pass Snell, but unless there's a sticker in the helmet, you can't
be sure.  Snell also tests samples of certified helmets to make sure
they still meet the standards.

According to Bell Helmets, the shelf life of their helmets is 8 years.

------------------------------

Subject: 9.5  Terminology
From: David Keppel <[e-mail]>,
      Charles Tryon  <[e-mail]>

Ashtabula Crank
    A one-piece crank -- the crank arm starts on one side of the
    bike, bends to go through the bottom bracket, and bends
    again on the other side to go down to the other pedal.
    Typically heavy, cheap, and robust.  See ``cottered crank''
    and ``cotterless crank''.  Ashtabula is the name of the
    original manufacturer, I think.

Biopace Chainring

    Chainrings that are more oval rather than round.  The idea was
    to redistribute the forces of pedaling to different points as your
    feet go around, due to the fact that there are "dead spots" in the
    stroke.  The concensus is pretty much that they work ok for
    novices, but get in the way for more experienced riders.

Cassette Freewheel

    A cassette freewheel is used with a freehub.  The part of
    a normal freewheel that contains the pawls that transfer
    chain motion to the wheel (or allows the wheel to spin
    while the chain doesn't move) is part of the wheel hub.
    The cassette is the cogs, usually held together with small
    screws.

Cleat

    A cleat attaches to the bottom of a cycling shoe.  Older style
    cleats have a slot that fits over the back of the pedal,
    and in conjunction with toe clips and straps, hold your foot
    on the pedal.  New "clipless" pedals have a specially designed
    cleat that locks into the pedal, sometimes with some ability
    to move side-to-side so as not to stress knees.

Cottered Crank
    A three-piece crank with two arms and an axle.  The arms
    each have a hole that fits over the end of the axle and a
    second hole that runs tangential to the first.  The crank
    axle has a tangential notch at each end.  A *cotter* is a
    tapered and rounded bar of metal that is inserted in the
    tangential hole in the crank arm and presses against the
    tangential notch in the crank axle.  The cotter is held in
    place by a nut screwed on at the thin end of the cotter.
    Ideally, the cotter is removed with a special tool.  Often,
    however, it is removed by banging on it with a hammer.  If
    you do the latter (gads!) be sure (a) to unscrew the nut
    until the end of the cotter is nearly flush, but leave it on
    so that it will straighten the threads when you unscrew it
    farther and (b) brace the other side of the crank with
    something very solid (the weight of the bike should be
    resting on that `something') so that the force of the
    banging is not transmitted through the bottom bracket
    bearings.

Cotterless Crank
    A three-piece crank with two arms and an axle.  Currently
    (1991) the most common kind of crank.  The crank axle has
    tapered square ends, the crank arms have mating tapered
    square ends.  The crank arm is pressed on and the taper
    ensures a snug fit.  The crank arm is drawn on and held in
    place with either nuts (low cost, ``nutted'' cotterless
    cranks) or with bolts.  A special tool is required to remove
    a cotterless crank.

Crank Axle
    The axle about which the crank arms and pedals revolve.  May
    be integrated with the cranks (Ashtabula) or a separate
    piece (cottered and cotterless).

Fender
    Also called a ``mudguard''.  Looked down upon by tweak
    cyclists, but used widely in the Pacific Northwest and many
    non-US parts of the world.  Helps keep the rider cleaner and
    drier.  Compare to ``rooster tail''.

Frame Table
    A big strong table that Will Not Flex and which has anchors
    at critical places -- dropouts, bottom bracket, seat, head.
    It also has places to attach accurate measuring instruments
    like dial gauges, scratch needles, etc.  The frame is clamped
    to the table and out-of-line parts are yielded into alignment.

High-Wheeler
    A bicycle with one large wheel and one small wheel.  The
    commonest are large front/small rear.  A small number are
    small front/large rear.  See ``ordinary'' or
    ``penny-farthing'' and contrast to ``safety''.

Hyperglide Freewheel

    Freewheel cogs with small "ramps" cut into the sides of the cogs
    which tend to pull the chain more quickly to the next larger cog
    when shifting.

Ordinary
    See ``penny-farthing''.

Penny-Farthing
    An old-fashioned ``high wheeler'' bicycle with a large
    (60", 150cm) front wheel and a much smaller rear wheel, the
    rider sits astride the front wheel and the pedals are
    connected directly to the front wheel like on many
    children's tricycles.  Also called ``ordinary'', and
    distinguished from either a small front/large rear high
    wheeler or a ``safety'' bicycle.

Rooster Tail
    A spray of water flung off the back wheel as the bicycle
    rolls through water.  Particularly pronounced on bikes
    without fenders.  See also ``fender''.

Safety
    Named after the ``Rover Safety'' bicycle, the contemporary
    layout of equal-sized wheels with rear chain drive.  Compare
    to ``ordinary''.

Spindle
    See ``crank axle''.

Three-Piece Crank
    A cottered or cotterless crank; compare to Ashtabula.

------------------------------

Subject: 9.6  Avoiding Dogs
From: Arnie Berger <[e-mail]>

  There are varying degrees of defense against dogs.

  1- Shout "NO!" as loud and authoritatively as you can. That works more
     than half the time against most dogs that consider chasing you just
     good sport.

  2- Get away from their territory as fast as you can.

  3- A water bottle squirt sometimes startles them.

  4- If you're willing to sacifice your pump, whump'em on the head when they
     come in range.

  If they're waiting for you in the road and all you can see are teeth
  then you in a heap o' trouble. In those situations, I've turned around,
  slowly, not staring at the dog, and rode away. When I have been in a stand
  off situation, I keep the bike between me and the dog.

  "Halt" works pretty well, and I've used it at times. It's range is about 8
   feet.

   I bought a "DAZER", from Heathkit. Its a small ultrasonic sound generator
   that you point at the dog. My wife and I were tandeming on a back road and
   used it on a mildly aggressive German Shephard. It seemed to cause the
   dog to back off.

   By far, without a doubt, hands down winner, is a squirt bottle full of
   reagent grade ammonia, fresh out of the jug. The kind that fumes when
   you remove the cap. When I lived in Illinois I had a big, mean dog that
   put its cross-hairs on my leg whenever I went by. After talking to the
   owner (redneck), I bought a handebar mount for a water bottle and loaded
   it with a lab squirt bottle of the above mentioned fluid. Just as the
   dog came alongside, I squirted him on his nose, eyes and mouth. The dog
   stopped dead in his tracks and started to roll around in the street.
   Although I continued to see that dog on my way to and from work, he
   never bothered me again.

   Finally, you can usually intimidate the most aggressive dog if there are
   more than one of you. Stopping, getting off your bikes and moving towards
   it will often cause it to back off. ( But not always ). My bottom line
   is to alway ride routes that I'm not familiar with, with someone else.

   As last resort, a nice compact, snubbed nose .25 caliber pistol will fit
   comfortably in your jersey pocket. :-)

------------------------------

Subject: 9.7  Shaving Your Legs

 How to do it  (Garth Somerville  [e-mail])

  Many riders shave their legs and have no problems other than
  a nick or two once in a while.  Maybe a duller blade would help.
  But some people (like me) need to be more careful to avoid
  rashes, infections (which can be serious), or just itchy legs that
  drive you to madness.  For those people, here is my
  leg shaving procedure:

  Each time you shave your legs...
  1) Wash your legs with soap and water, and a wash cloth. This
     removes dirt, oil, and dead skin cells.
  2) Use a good blade and a good razor. I prefer a blade that has
     a lubricating strip (e.g. Atra blades).  It is my personal
     experience that a used blade is better than a new one.  I
     discard the blade when the lubricating strip is used up.
  3) USE SHAVING CREAM. I prefer the gell type, and the kinds with
     aloe in them seem to be the best.  Shaving cream gives you a
     better shave with fewer cuts, and goes a long way towards
     preventing infection.
  4) Use *COLD* water.  Do not use hot water, do not use warm water,
     use the coldest water you can stand. Run the cold water over your
     legs before you start, and rinse the blade often in cold water.
  5) Be careful, and take your time. Behind the knees, and around the
     achilles  tendon are places to be extra careful.
  6) When finished, use a moisturizing lotion on your legs.


Why shave legs  (Jobst Brandt  [e-mail])

Oh wow, after the initial responses to this subject I thought we could
skip the posturing.  The reason for shaving legs is the same for
women, weight lifters, body builders and others who have parts of
their bodies that they choose to display.  It is not true that General
Schwarzkopf had all the troops shave their legs and arms before going
into combat to prevent infectious hair from killing injured soldiers,
and I am sure it will never happen.

Not only the shaving but the rub-downs with all sorts of oils at the
bike track are for the same reason bodybuilders oil up.  It reflects
well from the muscle defo.  Of course there are others who claim you
can't get a massage without shaving.  There is no medical proof that
hair presents any hazard when crashing on a road with dirt that gets
into a wound.  It must all be thoroughly cleaned if it goes beyond
superficial road rash.

From my experience with cyclists from east block countries before
Glasnost, none of them shaved because it was not in their charter to
look beautiful but rather to win medals.

I think shaved legs look good and I don't mind saying so.  I just find
it silly that those who shave need to put it forth as a preparation
for crashing.  Is it necessary to find a reason other than vanity?  If
you believe these stories then you might consider the whole pile of
lore in bicycling that also has no foundation in fact but is often
retold.  But then some bicyclists and followers of other pursuits,
want to believe in the mysteries that are handed down by the elders
and must be taken on faith.  It forms proof of initiation for some.

------------------------------

Subject: 9.8  Contact Lenses and Cycling
From: Robert A. Novy <[e-mail]>

I received on the order of 50 replies to my general query about contact lenses
and bicycling.  Thank you!  To summarize, I have been wearing glasses for
nearly all of my 28 years, and taking up bicycling has at last made me weary of
them.

I visited an optometrist last week, and he confirmed what I had lightly feared:
 I am farsighted with some astigmatism, so gas-permeable hard lenses are the
ticket.  He has had about a 25% success rate with soft lenses in cases such as
mine.  I am now acclimating my eyes to the lenses, adding one hour of wear per
day.  In case these don't work out, I'll try two options.  First, bicycle
without prescription lenses (my sight is nearly 20-20 without any).  Second,
get a pair of prescription sport glasses.

I had a particular request for a summary, and this is likely a topic of great
interest, so here goes.  Please recognize the pruning that I must do to draw
generalizations from many opinions.  Some minority views might be overlooked.
There is one nearly unanimous point:  contact lenses are much more convenient
than eyeglasses.  I had to add the word "nearly" because I just saw one voice
of dissent.  Sandy A. ([e-mail]) has found that prescription
glasses are better suited to mountain biking on dusty trails.

You can call me Doctor, but I have no medical degree.  This is only friendly
advice from a relatively ignorant user of the Internet.  See the first point
below!

IN GENERAL

+  Get a reputable optometrist or ophthalmologist.  Your eyes are precious.
[Paul Taira ([e-mail]) even has an iterative check-and-balance
setup between his ophthalmologist and a contact lens professional.]

+  Wear sunglasses, preferably wrap-arounds, to keep debris out of eyes, to
keep them from tearing or drying out, and to shield them from ultraviolet rays,
which might or might NOT be on the rise.

+  Contacts are not more hazardous than glasses in accidents.

+  Contacts improve peripheral and low-light vision.

+  Extended-wear soft lenses are usually the best.  Next come regular soft
lenses and then gas-permeable hard lenses.  Of course, there are dissenting
opinions here.  I'm glad to see that some people report success with gas perms.

+  One's prescription can limit the types of lenses available.  And soft lenses
for correcting astigmatisms seem pesky, for they tend to rotate and thus
defocus the image.  This is true even for the new type that are weighted to
help prevent this.  Seems that near-sighted people have the most choices.

+  If one type or brand of lens gives discomfort, try another.  Don't suffer
with it, and don't give up on contact lenses altogether.

BEWARE

+  Some lenses will tend to blow off the eye.  Soft lenses are apparently the
least susceptible to this problem.

PARTICULAR SUGGESTIONS

+  Consider disposable lenses.  They may well be worth it.

+  Carry a tiny bottle of eye/lens reconditioner and a pair of eyeglasses just
in case.

A POSSIBLE AUTHORITY

From David Elfstrom ([e-mail]):
  Hamano and Ruben, _Contact Lenses_, Prentice-Hall Canada, 1985, ISBN
0-13-169970-9.
I haven't laid hands on it, but it sounds relevant.

------------------------------

Subject: 9.9  How to deal with your clothes

When you commute by bike to work, you'd probably like to have clean
clothes that don't look like they've been at the bottom of your closet
for a couple of years.  Here are some suggestions for achieving this
goal:

  Take a week's worth of clothes to work ahead of time and leave them
  there.  You'll probably have to do this in a (gasp!) car.  This
  means that you'll need room in your office for the clothes.

  Carefully pack your clothes in a backpack/pannier and take them to
  work each day.  It has been suggested that rolling your clothes
  rather than folding them, with the least-likely to wrinkle on the
  inside.  This method may not work too well for the suit-and-tie
  crowd, but then I wouldn't know about that.  :-)

I use the second method, and I leave a pair of tennis shoes at work so
I don't have to carry them in.  This leaves room in my backpack for
a sweatshirt in case it's a cool day.

------------------------------

Subject: 9.10  Pete's Winter Cycling Tips
From: Pete Hickey <[e-mail]>

I am a commuter who cycles year round.  I have been doing it
for about twelve years.  Winters here in Ottawa are
relatively cold and snowy.  Ottawa is the second coldest
capital in the world.  The following comments are the
results my experiences.  I am not recommending them, only
telling you what works for me.  You may find it useful, or
you may find the stupid things that I do are humorous.

PRELUDE

Me:

I am not a real cyclist.  I just ride a bicycle.  I have
done a century, but that was still commuting.  There was a
networking conference 110 miles away, so I took my bicycle.
There and back. (does that make two centuries?)  I usually
do not ride a bicycle just for a ride.  Lots of things I say
may make real cyclists pull out their hair.  I have three
kids, and cannot *afford* to be a bike weenie.

People often ask me why I do it....  I don't know.  I might
say that it saves me money, but no.  Gasoline produces more
energy per dollar than food. (OK, I suppose if I would eat
only beans, rice and pasta with nothing on them.... I like
more variety) Do I do it for the environment?  Nah!  I never
take issues with anything.  I don't ride for health,
although as I get older, I appreciate the benefits.  I guess
I must do it because I like it.


Definitions

Since words like "very", "not too", etc. are very
subjective, I will use the following definitions:

    Cold : greater than  15 degrees F
    Very cold : 0 through 15 Degrees F
    Extreme cold : -15 through 0 degrees F
    Insane cold: below -15 degrees F


Basic philosophy

I have two:

    1) If its good, don't ruin it, if its junk you
       needn't worry.

    2) I use a brute force algorithm of cycling: Pedale
       long    enough, and you'll get there.

Bicycle riding in snow and ice is a problem of friction:
Too much of the rolling type, and not enough of the sideways
type.


Road conditions:

More will be covered below, but now let it suffice to say
that a lot of salt is used on the roads here.  Water
splashed up tastes as salty as a cup of Lipton Chicken soup
to which an additional spool of salt has been added. Salt
eats metal.  Bicycles dissolve.

EQUIPMENT:

Bicycle:

Although I have a better bicycle which I ride in nice
weather, I buy my commuting bikes at garage sales for about
$25.00. They're disposable.  Once they start dissolving, I
remove any salvageable parts, then throw the rest away.

Right now, I'm riding a '10-speed' bike.  I used to ride
mountain bikes, but I'm back to the '10-speed'.  Here's why.
Mountain bikes cost $50.00 at the garage sales.  They're
more in demand around here. Since I've ridden both, I'll
comment on each one.

The Mountain bikes do have better handling, but they're a
tougher to ride through deep snow.  The 10-speed cuts
through the deep snow better.  I can ride in deeper snow
with it, and when the snow gets too deep to ride, its easier
to carry.

Fenders on the bike?  Sounds like it might be a good idea,
and someday I'll try it out.  I think, however, that
snow/ice will build up between the fender and the tire
causing it to be real tough to pedal.  I have a rack on the
back with a piece of plywood to prevent too much junk being
thrown on my back.

I would *like* to be able to maintain the bike, but its
tough to work outside in the winter.  My wife (maybe I
should write to Dear Abbey about this) will not let me bring
my slop covered bicycle through the house to get it in the
basement.  About once a month We have a warm enough day that
I am able to go out with a bucket of water, wash all of the
gunk off of the bike, let it dry and then bring it in.

I tear the thing down, clean it and put it together with
lots of grease.  I use some kind of grease made for farm
equipment that is supposed to be more resistant to the
elements.  When I put it together, I grease the threads,
then cover the nuts, screws, whatever with a layer of
grease.  This prevents them from rusting solidly in place
making it impossible to remove.  Protection against
corrosion is the primary purpose of the grease.  Lubrication
is secondary. remember to put a drop of oil on the threads
of each spoke, otherwise, the spokes rust solidly, and its
impossible to do any truing

Outside, I keep a plastic ketchup squirter, which I fill with
automotive oil (lately its been 90 weight standard
transmission oil).  Every two or three days, I use it to re-
oil my chain and derailleur, and brakes.  It drips all over
the snow beneath me when I do it, and gets onto my
'cuffs'(or whatever you call the bottom of those pants.
See, I told you I don't cycle for the environment.  I
probably end up dumping an ounce of heavy oil into the snow
run-off each year.


Clothing

Starting at the bottom, on my feet I wear Sorell Caribou
boots. These are huge ugly things, but they keep my feet
warm.  I have found that in extreme to insane cold, my toes
get cold otherwise. These boots do not make it easy to ride,
but they do keep me warm (see rule 2, brute force).  They do
not fit into any toe-clips that I have seen.  I used to wear
lighter things for less cold weather, but I found judging
the weather to be a pain.  If its not too cold, I ride with
them half unlaced.  The colder it gets, the more I lace
them, and finally, I'll tie them.

Fortunately, wet days are not too cold, and cold days are
not wet.  When its dry, I wear a pair of cycling shorts, and
one or two (depending on temp and wind) cotton sweat pants
covering that.  I know about lycra and polypro (and use them
for skiing), but these things are destroyed by road-dirt,
slush and mud.(see rule 1 above).  I save my good clothes
for x-country skiing.

An important clothing item in extreme to insane cold, is a
third sock.  You put it in your pants.  No, not to increase
the bulge to impress the girls, but for insulation.
Although several months after it happens it may be funny,
when it does  happens, frostbite on the penis is not funny.
I speak from experience!  Twice, no less!  I have no idea
of what to recommend to women in this section.

Next in line, I wear a polypro shirt, covered by a wool
sweater, covered by a 'ski-jacket' (a real ugly one with a
stripe up the back.  The ski jacket protects the rest of my
clothes, and I can regulate my temperature with the zipper
in front.

I usually take a scarf with me.  For years I have had a fear
that the scarf would get caught in the spokes, and I'd be
strangled in the middle of the street, but it has not yet
happened.  When the temp is extreme or colder, I like
keeping my neck warm.  I have one small problem.  Sometimes
the moisture in my breath will cause the scarf to freeze to
my beard.

On my hands, I wear wool mittens when its not too cold, and
when it gets really cold, I wear my cross-country skiing
gloves (swix) with wool mittens covering them.  Hands sweat
in certain areas (at least mine do), and I like watching the
frost form on the outside of the mittens.  By looking at the
frost, I can tell which muscles are working.  I am amused by
things like this.

On my head, I wear a toque (Ski-hat?) covered by a bicycle
helmet. I don't wear one of those full face masks because I
haven't yet been able to find one that fits well with eye
glasses.  In extreme to insane cold, my forehead will often
get quite cold, and I have to keep pulling my hat down.  The
bottoms of my ears sometimes stick out from my hat, and
they're always getting frostbitten. This year, I'm thinking
of trying my son's Lifa/polypro balaclava. Its thin enough
so that it won't bother me, and I only need a bit more
protection from frostbite.

I carry my clothes for the day in a knapsack.  Everything that
goes in the knapsack goes into a plastic bag.  Check the plastic
bag often for leaks.  A small hole near the top may let in water
which won't be able to get out.  The net result is that things
get more wet than would otherwise be expected.  The zippers will
eventually corrode.  Even the plastic ones become useless after
a few years.


RIDING:

In the winter, the road is narrower.  There are snow banks
on either side.  Cars do not expect to see bicycles.  There
are less hours of daylight, and the its harder to maintain
control of the bicycle. Be careful.

I don't worry about what legal rights I have on the road, I
simply worry about my life.  I'd rather crash into a snow
bank for sure rather than take a chance of crashing into a
car.  I haven't yet had a winter accident in 12 years.  I've
intentionally driven into many snow banks.

Sometimes, during a storm, I get into places where I just
can't ride.  It is sometimes necessary to carry the bicycle
across open fields.  When this happens, I appreciate my
boots.

It takes a lot more energy to pedal.  Grease gets thick, and
parts (the bicycle's and mine) don't seem to move as easily.
My traveling time increases about 30% in nice weather, and
can even double during a raging storm.

The wind seems to be always worse in winter.  It's not
uncommon to have to pedal to go down hills.

Be careful on slushy days.  Imagine an 8 inch snowfall
followed by rain.  This produces heavy slush.  If a car
rides quickly through deep slush, it may send a wave of the
slush at you. This stuff is heavy.  When it hits you, it
really throws you off balance.  Its roughly like getting a
10 lbs sack of rotten potatoes thrown at your back.  This
stuff could even knock over a pedestrian.

Freezing rain is the worst.  Oddly enough, I find it easier
to ride across a parking lot covered with wet smooth ice
than it is to walk across it.  The only problem is that
sometimes the bicycle simply slides sideways out from under
you.  I practice unicycle riding, and that may help my
balance.  (Maybe not, but its fun anyway)

Beware of bridges that have metal grating.  This stuff gets
real slippery when snow covered.  One time, I slid, hit an
expansion joint, went over the handle bars, over the railing
of the bridge.  I don't know how, but one arm reached out
and grabbed the railing.  Kind of like being MacGyver.


Stopping.

There are several ways of stopping.  The first one is to use
the brakes.  This does not always work.  Breaks can ice up,
a bit of water gets between the cable and its sheathing when
the warm afternoon sun shines on the bike. It freezes solid
after. Or the salt causes brake cables to break, etc.  I
have had brakes work on one corner, but stop working by the
time I get to the next.  I have several other means of
stopping.

The casual method.  For a stop when you have plenty of time.
Rest the ball of your foot on top of the front derailleur,
and *gradually* work your heel between the tire and the
frame. By varying the pressure, you can control your speed.
Be sure that you don't let your foot get wedged in there!

Faster method.  Get your pedals in the 6-12 O'clock
position. Stand up.  The 6 O'clock foot remains on the
pedal, while you place the other foot on the ground in front
of the pedal.  By varying your balance, you can apply more
or less pressure to your foot.  The pedal, wedged against
the back of your calf, forces your foot down more, providing
more friction.

Really fast!  Start with the fast method, but then dismount
while sliding the bicycle in front of you.  You will end up
sliding on your two feet, holding onto the bike in front for
balance.  If it gets *really* critical, throw the bike ahead
of you, and sit down and roll.  Do not do this on dry
pavement, your feet need to be able to slide.

In some conditions, running into a snow bank on the side
will stop you quickly, easily, and safely.  If you're going
too fast, you might want to dive off of the bicycle over the
side.  Only do this when the snow bank is soft.  Make sure
that there isn't a car hidden under that soft snow.  Don't
jump into fire hydrants either.


ETC.

Freezing locks.  I recommend carrying a BIC lighter.  Very
often the lock will get wet, and freeze solid.  Usually the
heat from my hands applied for a minute or so (a real minute
or so, not what seems like a minute) will melt it, but
sometimes it just needs more than that.

Eating Popsicles

Something I like doing in the winter is to buy a Popsicle
before I leave, and put it in my pocket.  It won't melt!  I
take it out and start eating it just as I arrive at the
University.  Its fun to watch peoples' expressions when they
see me, riding in the snow, eating a Popsicle.


You have to be careful with Popsicles in the winter.  I once
had a horrible experience.  You know how when you are a kid,
your parents told you never to put your tongue onto a metal
pole? In very cold weather, a Popsicle acts the same way.
If you are not careful, your upper lip, lower lip, and
tongue become cemented to the Popsicle.  Although this
sounds funny when I write about it, it was definitely not
funny when it happened.

------------------------------

Subject: 9.11  Nancy's Cold/Wet Cycling Tips
From: Name removed by request

Here are some clothing suggestions, mix and match as you wish:

Rain gear : I forked out the dollars for gore-tex when I did a week tour
  ... and I'm real glad I did. The stuff works reasonably as claimed,
  waterproof, and relatively breathable. (When the humidity is high, no
  fabric will work completely at letting sweat evaporate.) Unfortunately,
  typical prices are high. There are cheaper rainsuits, which I haven't tried.
  For short rides, or when the temperature is over about 50F, I don't
  usually wear the rain pants, as wet legs don't particularly bother me.

Waterproof shoe covers. When the weather gets icky, I give up on
  the cleats (I'm not riding for performance then, anyway) and put
  the old-style pedals back on. This is basically because of the
  shoe covers I have that work better with touring shoes. The ones
  I have are made by Burley, and are available from Adventure Cycling Association,
  though I got them at a local shop. They are just  the cover, no
  insulation. I continue to use them in winter since they are windproof,
  and get the insulation I need from warm socks. These aren't neoprene,
  but rather some high-tech waterproof fabric.

Gaiters that hikers and cross-country skiers wear can help keep road
  spray off your legs and feet.

Toe clip covers. I got them from Nashbar; they are insulated and fit
  over the toe clips ... another reason for  going back to those pedals.
  They help quite a bit when the temperature goes into the 30's and below;
  they are too warm above that.

  [Joshua Putnam <[e-mail]> reports:
   Nashbar has apparently discontinued its toe clip covers.

   Traditional toe clip covers, also called toe warmers, are still
   made by Kucharik Bicycle Clothing.  Kucharik's model is not
   insulated, just waterproof nylon cloth.  It may be hard to find
   a shop that carries them, but if you have a good relationship
   with your local shop, they might be interested in dealing with
   Kucharik, which also makes great wool jerseys and tights, arm and
   leg warmers, etc.

   The company is:

   Kucharik Clothing
   1745 W 182nd St
   Gardena, CA  90248

   Please remember that this is a manufacturer/distributor, not a
   mail order catalog.  ]

For temperatures in the 40's I usually find that a polypropylene shirt,
  lightweight sweater (mine is polypro) and wind shell work well; I use
  the gore-tex jacket, since I have it, but any light weight jacket
  is OK. I have a lightweight pair of nylon-lycra tights, suitable in
  the 50's, and maybe the 40's; a heavier pair of polypro tights, for
  40's, and a real warm pair of heavy, fleece-lined tights for colder
  weather. (I have been comfortable in them down to about 15-deg, which
  is about the minimum I will ride in.) My tights are several years
  old, and I think there are lots more variations on warm tights out now.
  I use thin polypro glove liners with my cycling gloves when it is a little
  cool; lightweight gloves  for a little bit cooler; gore-tex and thinsulate
  gloves for cold weather (with the glove liners in the really cold weather.)
  It is really my fingers that limit my cold weather riding, as anything
  any thicker than that limits my ability to work brake levers.
  (Note: this may change this year as I've just bought a mountain bike;
  the brake levers are much more accessible than on my road bike. It may
  be possible to ride with warm over-mitts over a wool or similar glove.)

When it gets down to the 20's, or if it's windy at warmer (!)  temperatures,
  I'll add the gore-tex pants from my rain suit, mostly as wind protection,
  rather than rain protection. Cheaper wind pants are available (either
  at bike shops or at sporting goods stores) that will work just as well
  for that use.

Warm socks. There are lots of choices; I use 1 pair of wool/polypropylene
  hiking socks (fairly thick). Then with the rain covers on my shoes to
  keep out wind, and (if necessary) the toe clip covers, I'm warm enough.
  There are also thin sock liners, like my glove liners, but I haven't
  needed them; there are also neoprene socks, which I've never tried,
  and neoprene shoe covers, which I've also never tried, and wool socks,
  and ski socks ...

I have a polypropylene balaclava which fits comfortably under my helmet;
  good to most of the temperatures I'm willing to ride in; a little too
  warm for temperatures above freezing, unless it's also windy. I also have
  an ear-warmer band, good for 40's and  useful with the balaclava for
  miserable weather. I also have a neoprene face mask; dorky looking, but
  it works. It is definitely too hot until the temperature (or wind) gets
  severe. I sometimes add ski goggles for the worst conditions, but they
  limit peripheral vision, so I only use   them if I'm desperate.

For temperatures in the 30's, and maybe 20's, I wear a polarfleece
  pullover thing under the outer shell. Combining that with or without
  polypro (lightweight) sweater or serious duty wool sweater gives a
  lot of options. Sometimes I add a down vest -- I prefer it *outside*
  my shell (contrary to usual wisdom) because I usually find it too
  warm once I start moving and want to unzip it, leaving the wind
  shell closed for wind protection. I only use the down vest when it's
  below about 15 F.