Usenet 1993 July/InfoMagic USENET CD-ROM July 1993.ISO/answers/rec-skate-faq/part2

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From: [e-mail] (Tony Chen)
Subject: Rec.skate FAQ:  Wheels, Bearings, and Brakes (2/8)
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Posted-By: auto-faq 1.24
Archive-name: rec-skate-faq/part2


REC.SKATE FAQ - PART 2:  WHEELS, BEARINGS, AND BRAKES


                                 Inline Wheels
                                 -------------
                             (written May 17, 1992)
                          (last changed Sept 10, 1992)


TECHNICAL INFO

Inline wheels are made of polyurethane.   Although wheels are classified
on three criteria: diameter, durometer (hardness), and rebound, you will
usually see only the diameter and durometer marked on the wheels and/or
packaging (e.g.,76mm 78A, or 70mm 82A, etc.).


DIAMETER

The diameter of the wheel is basically how tall the wheel is.  The usual
diameters are 80mm, 77mm, 76mm, 72.5mm, 72mm, and 70mm.  More recently,
82mm wheels have been introduced.  Generally, racing skates will fit up
to 82mm wheels, high-end skates up to 77mm, and the rest of the models
up to 72.5mm.  Although these are the designed ranges, skates can take
slightly taller wheels than what they're supposed to.  For instance, the
Bauer XF/3's, with the front and heel wheel spacers moved in (for a
shortened wheelbase), can use 76mm wheels for all four positions.
Extension modification (i.e., scraping down) of skates are need for
wheels much larger than the intended size.

Although still subject to some technical debate, in general, taller
wheels will let you go faster (i.e., 76mm are faster than 70mm) but
there is a point where taller wheels will only make you go slower with
added weight (harder to start rolling) and less manueverability.

Shorter wheels are cheaper, but in general don't last as long since they
have less material to wear down overall.


DUROMETER (hardness):

Durometer is a relative hardness measure frequently used for rubber and
plastic products.  There are several scales, with the "A" scale (hence
the 78A, etc.) used for wheels.  The number is the rating from 0-100,
with 0 being no resistance and 100 being very hard plastic.

Inline wheels generally run from 74A to 93A, with 78A, 82A, and 85A
being the most common.  For outdoors, the softer the wheel, the better
the shock absorption on bumps, cracks, pebbles and other vibrations.
The trade-off is that softer wheels last a shorter time.  Harder wheels,
since they have less drag, are preferred on indoor surfaces which are
usually very smooth.

Hockey players may prefer harder wheels because it allows them to slide
somewhat.


Rebound:
This is how much the wheel will return the energy when your wheels are
compressed.  So a higher rebound, will provide more response on each
stroke.  There doesn't seem to be a rebound scale (is there?) as there
is for durometer.


HUBS

The hubs are very important to the overall performance of the wheel.
Hubs which are too large will not hold the bearings tightly enough.
This can allow the wheel to become "cocked" so that it rubs against the
frame.  Only one wheel needs to be out of alignment to mess things up.

This is a serious problem, not only because it causes drag, but because
it heats up the wheel which will soon cause it to seperate from the hub
and expand, which will very soon destroy the wheel.

I have noticed this on several sets of Kryptonics Turbocores.  The
first sign is that the wheels creak as you switch your weight on the
skate. And if you remover the wheel from the frame, there will be a arc
clear of dirt and dust where the wheel was rubbing.

If you notice this, put your hands on your wheels after a long fast
skate and see if any of them are much warmer than the others.  If so,
they are probably rubbing.

This can happen a lot easier on frames like the Mogema and the Darkstar
that have very close tolerences and the side of the frame is close to
the side of the wheel.  I'm not sure if is as big as a problem (or a
problem at all) for recreational skates like the Areoblade.  But the
creaking is bothersome in any event.


AXLE KITS

Another important aspect of your wheels is the axles that go with them.
There are several axle replacement kits (such as the Hyper Hop-up Kit
and the Blading Edge Kit) designed to let your wheels roll much faster
than with your stock axles. These kits are usually made of aluminium and
steel.  What they consist of is two axles per wheel, each screwing into
the threaded bushing in the wheel. This also prevents overtightening,
which is common with the regular axle system.  When putting your wheels
back, make sure the wheels are just snug enough so they don't move
around.  Anything more just increases the friction on your bearings.


MAINTENANCE

Wheels of any durometer will wear out, given enough mileage.  There's
only so much polyurethane on your wheels, while there's thousands of
miles of asphalt out there (a slightly different story for indoor
skating, but wearage occur nevertheless).  Your wheels are due for
maintenance when your skates are much  slower and not rolling as
smoothly as when new.  The inside edges will wear more quickly, which
you will eventually notice.

There are two things to do to increase the life of your wheels:  rotate
them and flip them.  Rotating your wheels means to switch the positions
of the wheels.  Different positions (like the heel or toe wheels)
receive varying amounts of wear.  By rotating the wheels, you can even
out the wear each wheel receives.

Flipping your wheels means to turn each wheel so that the worn edge now
faces the outside.  This lets you wear down the other portion of the
wheels.

There are several patterns for wheel rotation.  The one you use isn't
crucial.  The main point is to maintain an even wear on your wheels and
to extend the amount of mileage you can get.  Feel free to swap wheels
until you feel you have a good distribution on your skates.

Some rotation patterns:

The front wheel is "1" and the back wheel is either "4" or "5".

For 3-wheel skates:  3->2, 2->1, 1->3

For 4-wheel skates:  4<->2, 3<->1                   OR     4->3 3->2 2-
>1 1->4

For 5-wheel skates:  5->3, 4->2, 3->1, 2->5, 1->4   OR   5->3, 4->5, 3-
>2, 2->4

In addition to rotating and flipping your wheels, you should also wipe
off your skates, rails, wheels and bearings with a damp cloth.  This
keeps the amount of dirt on your skates and wheels to a minimum.


ROCKERING YOUR SKATES

Having skates non-rockered means the axles and wheels are all at the
same height This is the way the skates come when you buy then.  What
many skates allow you  to do is to change the height of some or all of
the axles, to provide a different "blade" to skate on.  Rockered skates
then, have the middle two wheels lower relative to the front and heel
wheels.  This is accomplished by having oval spacers with an offset
axle-hole.  So each spacer can have an up or down position.

Racing skates are also adjustable, but only in the horizontal direction,
allowing for a longer or shorter wheelbase.

Although subject to some disagreement, many skaters find rockering
provides much more maneuverability due to the curved "blade" of the
wheels.  Whether you rocker or not is really up to you.  Many hockey
players prefer to have their skates rockered for sharper turns on the
court, while racers keep their blades flat for more stability at high
speeds (rockers at high speed will produce speed wobble).  Artisitic
skaters may also prefer rockered, while extreme skaters may
stay flat.

Depending on your skates, there are various rockering configurations
possible.  If your skates can adjust the height of only the middle two
wheels, you can have your skates flat or rockered:

Flat : ==frame==

        1 2 3 4


Rockered: ==frame==
           1     4
             2 3

If your skates can adjust the height of all four wheels then you have
the positions of


short even rocker: ==frame==    (wheels closer to boot, for more
control)
                    1      4
                      2  3

tall even rocker:  ==frame==    (taller, for sharper turns)

                    1       4
                      2  3

front-lift rocker: ==frame==    (a little more stable than regular
rocker)
                   1
                      2  3  4

front-lift,      : ==frame==    (tilts skates forward)
rear-down, rocker  1
                      2  3
                            4



Wheels generally run from $4.25 to $8.00, depending on the quality and
size of the wheel.  The three inline wheel manufacturers are Kryptonics,
Inc. and Hyper Inline and Labeda.

==============================================================================

NEW WHEELS for '93

From: [e-mail] (Phil Earnhardt)
Subject: Hyper's 1993 wheel line

Here's a list of the various kinds of Hyper wheels available in 1993.  Note:
this is from their marketing literature; you may or may not be able to find
all of these wheels (particularly in all colors).

I'll include selections of the "hype" from the brochure. Your mileage may
vary.

Superlite "America's #1 preferred replacement wheel for all inline skates ...
increased traction, smoother roll ... [they'll] last longer ..."

72mm  78A teal, black, yellow, clear, pink, purple
72mm  82A teal, black, yellow, clear, pink, purple
72mm  85A black, pink, purple
72mm  93A teal, pink

76mm  78A teal, black, yellow, clear, pink, purple
76mm  82A purple, black

Redline Racing Series (tm) "Developed to win [races] ... more speed ... more
gold"

76mm  75A orange
76mm  78A yellow
76mm  82A purple
82mm  75A orange
82mm  78A yellow
82mm  82A purple

The 76mm skates are available with two different types of hubs: LS and
SS.  It's unclear from the brochure exactly what is different between
the two.

Hockey wheels "H-250 [wheel] compound for longer wear and increased slide
control. 'Big Foot' riding surface."

70mm  78A black, purple, clear, teal
70mm  82A black, purple, clear, teal
70mm  85A black, purple, clear, teal

"Fat Boys" "Fully tested for the ramp, pool, or street. Hubs are bonded
together with the 'Fat Boy' landing surface"

70mm  80A black, purple, yellow, silver
70mm  84A black, purple, yellow, silver

The brochure provides a fair number of guidelines for wheel choice.

The softer hockey wheels and the trick wheels are both welcome developments!


========================================================================

                          THE BEARING MAINTENANCE FILE
                          ----------------------------
                              (written May 2, 1992)
                           (last changed Jan 30, 1993)
                         Compiled and edited by Tony Chen

Contents:
* General Info
* Sealed or Shielded?
* Bearing ratings
* How to maintain your bearings
  1st method : If you don't mind taking off the seals.
  2nd method : If you don't want to pry off the seals.


GENERAL INFO

Inline skates all use 608 bearings.  The number means that the bearings
are from the 600 series, with a 8mm inner diameter (the width of the
hole i.e., internal bore).  The "6" appears to be for the 6mm difference
between the inner and outer radii (from the outside edge to the edge of
the hole).

608 bearings are also the standard size for skateboard bearings.  Quad
skates use either type 608 (8mm internal bore) or type 627 (7mm internal
bore).  The 608s for quads are the outdoor bearings. If your  bearings
have letters following the "608" (like "S", "Z", or even "ZZ" or "SS")
it is the manufacturer's way of denoting sealed or perhaps double
shielded bearings.  To make sure what they mean you should probably
check with the manufacturer, since it varies from company to company.

A little cross-reference on part numbers for bearings, the 7MM ones are
for quality indoor skates, the 8MM ones are used for in-lines, other indoor
skates and skateboards.

Double Shielded:
    NTN    Fafnir    MRC    ND    SKF    HCH    YW
7MM    627-ZZ    37KDD    37FF    77037    R7-2Z    627Z    60027
8MM    608-ZZ    38KDD    38FF    77038    R8-2Z

Double Sealed (neoprene rubber):
    NTN    Fafnir    MRC    ND    SKF
7MM    627-LL    37PP    37ZZ    99037    R7-2RS
8MM    608-LL    38PP    38ZZ    99038    R8-2RS

Single shielded/sealed bearings usually delete one of the doubled
prefix/suffix characters.  (Thanks go to George for the above chart).

Bearings for in-lines generally come grease filled.  Some bearings like
GMNs are sold either greased or oiled (but usually greased).


SEALED OR SHIELDED?

There are basically two types of bearings.  Most likely you will have
SHIELDED bearings, which most stock skates come with.  Shields will make
it hard for dirt and grime to get in, but they certainly aren't dust or
water tight.

There are also SEALED bearings, which have a teflon or rubber lip seal
that actually touches the brace, and come packed with a fairly heavy
grease.  Rollerblade sells sealed bearings under the name Max Trainers.
You may find other brands as well.  The advantage is that they should
last a long time without any maintenance at all.  The trade-off is that
these bearings generally cost more and you also encounter a much higher
rolling resistance.  Slower bearings are not necessarily bad, since many
people like the added resistance for a better workout.


BEARING RATINGS

Bearings are rated on the ABEC (the Annular Bearing Engineering Council)
scale.NMBs are rated ABEC-1, GMNs are ABEC-3, and Powell Swiss and
Fafnir are ABEC-5.  Buying bearings rated any higher than ABEC-5 will
probably not do any good since they aren't be meant for use in in-lines.
The higher precision will be lost to contaminating dust and dirt anyway.
(If it's speed you want cutting down wind-resistance and improving your
technique is probably a better way.)

Really precise bearings are only used in high speed (read: rotational)
applications, as in machinery.  The next higher grade up from in-line
bearings are in machines which are rotating at speeds of at least
10,000 rpm which is around 80+ mph.  You probably won't want to go that
fast on your skates 8-)  At 50,000 rpm you would be traveling 400+ mph.
So which happens first?  the wheels melting, or the skin ripping off the
skater?  Gives new meaning to shredding 8-)


WHEN TO CLEAN AND RE-LUBRICATE YOUR BEARINGS

Exposure to dirt and water are the main reason that your bearings slow
down.  Bad bearings will be the ones which don't let your wheels spin
for a respectable amount of time.  If you hear or feel the vibrations
of metal rubbing on metal, chances are, your bearings are in need of
some maintenance.

If some of the balls or bearing surfaces have become roughened, there's
basically nothing you can do.  They won't get any better, but they may
last a long time anyway.  You can always replace your bearings a few
at a time.

Take care of your bearings by cleaning and preping them as needed.
Assuming normal usage, they should last through several sets of wheels,
depending on how much skating you do.


REPLACING YOUR BEARINGS

You can replace your bearings if (1) any of your bearings have somehow
stopped spinning well, despite all the cleaning you do or (2) you want
to change to different types of bearings (racing or sealed or whatever).


HOW TO TAKE CARE OF YOUR BEARINGS

1. Remove your wheels from the skates, and push the bearings out with a
   spare bushing (the plastic/metal part that goes between the bearings)
   or one of the several types of bearing tools available on the market.


2. If you have Powell Swiss (Bones) bearings, simply pry off the
   removable plastic cap on each bearing.  If you have NMBs, GMNs
   (Germans), other shielded bearings, or sealed bearings, carefully
   puncture or pry off the shield (or seal) on one side. (Some people
   tell you to never pry off a seal, some say it's okay.  It's really up
   to you.  Whatever you do, lubrication always helps)

   When removing the covers of entire sets of bearings at once, be
   careful to only take off one cover per bearing.  Otherwise you'll be
   left with a shieldless/sealless bearing (which won't last long
   against outdoor conditions).

   Once you have the cover off, you should be able to see the ball
   bearings inside, held in place by a brace.  You won't need the old
   metal covers anymore.  In Bones bearings the cap is ALSO the brace,
   so you won't see a brace.  Bones users should obviously keep the
   plastic cap when reassembling their bearings.

   You don't want to take the ball bearings out since they aren't meant
   to be removed and replaced.


3. Soak the bearings in paint thinner, naphtha, Simple Green*, or any
   other handy solvent.  In any case, the choice of solvent isn't
   crucial so long as you can get all the dirt and old grease cleaned
   out.

   Avoid low-flash point solvents like gasoline, xylene, lacquer
   thinner, etc. which are dangerously flammable.  Also wear latex/chem
   lab gloves if possible.  Solvents are no fun to ingest or absorb
   through your skin.  An alternative is to use a pair of tongs or
   tweezers to handle your bearings.

   How long you soak depends on how dirty and dried out your bearings
   have gotten.  Previously maintained bearings won't need to soak very
   long.  Bearings that have gone dry and have lots of grit in them may
   need to soak overnight, or even several days.

   If necessary use a brush or swirl your bearings around in your
   container to make sure everything breaks loose.  Small coffee cans,
   peanut jars, or even the little black film canisters you get with new
   film, all make decent containers.  You don't really need large
   amounts of solvent.  Just enough to immerse your bearings.  You also
   don't need to refill with clean solvent with each bearing, unless the
   solvent you were using has gotten really dirty.  The essential thing
   is that the dirt and grease is broken up.  Step 4 will remove most of
   the gunk.

   WD-40 is generally not recommended as a solvent since it leaves a
   sticky, dust attracting film on the bearings.

   Ultrasonic cleaners is ideal for cleaning bearings.  If you have one
   or access to one, you can clean your bearings en mass and avoid
   getting your hands dirty.

   *Simple Green.  Just soak the parts in pure Simple Green and rinse
   with water.  Thoroughly dry everything off and lubricate immediately.
   Simple Green is water soluble, so take care to dry it well, since it
   can cause rust otherwise.

   Parts come out much cleaner and much faster than with other solvents.
   You should stay cleaner and there are no nasty fumes to inhale.
   Simple Green should be available in most grocery or hardware stores.




4. Now rinse out your bearings with hot, soapy water to make sure you
   clear out all the solvent.  You now have some clean bearings.

   Clean, unlubricated bearings appear to have the lowest amount of
   unloaded friction, but don't expect them to last very long if you
   skate on them.   After a fairly short time, the surface of the balls
   will start to flake   and roughen and they won't spin very well.


5. Use a hair dryer or just air/sun dry to make sure that all traces of
   water are gone.  Using a hair dryer or basking in the sun also preps
   the bearing nicely by heating the metal somewhat.


6. Now lubricate with your favorite lubricant.  You can use Tri-flow or
   one of the specialty lubricants distributed for bearings.  Bones
   bearings come with their own Speed Cream.

   You can use grease or oil as you prefer.  Oiled bearings have
   slightly less resistance, but need to be maintained more often (as
   often as once a week).  It is very helpful to have a little
   hypodermic style oiler with a long needle to let you put the oil
   right where you want it.

   Grease works well because after a while most of it gets shoved out of
   contact with the balls and only a little bit smears onto the
   workings.  However, newly greased (or heavy oil) bearings, will take
   a while to expel any extra grease and move the rest out of the way.

   For oiling, light oil, like sewing machine oil, or 5W-20 motor oil is
   a good choice.  Household oils (3-in-one, etc) may gum up after a
   while and the teflon-based lubricants have little particles of teflon
   that are only in the way.

   Some people recommend that you use a 50-50 mixture of lighter fluid
   and baby oil to lubricate your bearings.  This mix should result in
   not having to clean them out as often, only lubricate more often.

   Let the bearings sit for an hour, and wipe them off.


7. Put one bearing back into the  wheel, with the open face towards the
   inside of the wheel.  Insert the bushing and then put on the second
   bearing (with the open face towards the inside again).  It is pretty
   hard for contaminants to get into the bearings from the inside.


2ND METHOD (for keeping the shields on):

   First do Step 1 (from 1st Method).

   If your bearings are permanently sealed (or you don't want to remove
   the seals) you can still soak in solvent (see step 3) for several
   hours or as long as you feel necessary.  Enough solvent should soak
   through to remove some of the grease.

   Then you can lubricate the seams and/or press some in with your
   fingers.  Enough oil should seep through to lubricate your bearings
   (see step 6).

========================================================================


From: [e-mail] (Phil Earnhardt)
Message-ID: <[e-mail]>
Date: 8 Mar 92 04:03:01 GMT

First off, note that there are 3 types of brakes available for the Rollerblade
"square" brakes (used on current Rollerblade high-end skates -- Lightning,
Aeroblade, Racerblade, etc.):

    o Black Brakes. What used to come on the skates by default; what
      dealers stock as replacement brakes by default. Marking and squeaky.
    o TRS Brakes. They gray guys. About twice as expensive. Marking.
      Somewhat squeaky, but less than the black ones.
    o Polyurethane Brakes. These appeared near the end of the summer of
      1991. They come in bright blue, pink, green. Priced near the price
      of the TRS Brakes. No squeako at all (sometimes, they hum -- it's
      kind of nice). No marking at all. By my metric, they last longer
      than the Black guys but not quite as long as the TRS Brakes. The
      braking action is a bit grabby; some may view this as a problem.

WRT brake life, I'm sure you'll get some subjective opinions. However, I have
never observed the Poly brakes crumbling and coming off in chunks. Remember,
the wheels are just polyurethane, too -- do you see them come off in chunks?
It might be possible to lose chunks of polyurethane on extremely rough roads;
I'd recommend avoiding such surfaces.

=END OF PART 2==================================================================