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- Frequently Asked Questions (FAQS);faqs.482
-
-
-
- 3) Be careful about your capacities and specifications when posting;
- in the US we get a mix of Metric and English system values, whereas
- Europe is almost entirely on the Metric system. A future edition
- of this monthly posting will contain a list of commonly-used
- abbreviations that may not be known in some places that rec.autos
- reaches; this cuts both ways so let us not be parochial about it.
-
- 4) Use the Distribution: field to limit where your article goes, when
- possible. Within North America, the values na (north america), can
- (canada), and usa may be used. in addition, the two-letter state
- abbreviations of the US are supported in some cases; e.g. if i wanted
- to send an article only to New York and New Jersey, i could put
- "ny,nj" in a Distribution field. note that multiple, comma-separated
- values are legal. these distribution fields vary widely, however, so
- you should check with your local sysadmin to find out what is likely
- to be supported in your area.
-
- The Dangers of Overgeneralization:
-
- To amplify a warning from the distribution section of this article:
- Be wary of making foolish assumptions about all cars, tires, etc. What is
- true for a 1973 Buick with a 455cid engine may be quite utterly wrong for a
- 1976 Honda with a 1200cc engine. Headlight laws in Sweden are decidedly
- different from those in Idaho.
-
- The Need for Adequate Specification:
-
- When you ask a question, please give a reasonable amount of information;
- e.g., if you have a question about your Honda, please specify year,
- model, engine size, etc. Otherwise, most answers to your question may be
- quite useless.
-
-
- Concerning Lemons:
-
- At one time or another, every auto manufacturer has manufactured a lemon or
- two; even Honda admits to this. Please don't waste everyone's time by
- announcing to the world that your `brand x' automobile is terrible, so all
- `brand x' automobiles are terrible, so no one should ever buy a car from
- the `brand x' company. Such articles are worse than useless, because they
- cause substantial wasted bandwidth while carrying little or no useful
- information.
-
-
- Concerning Flames:
-
- As much as we might wish it, a flame-free newsgroup is something that most
- likely will never occur. Here are some guidelines for flames and how
- to deal with them (a list of flame-prone topics follows in the next section
- of this posting):
-
- If you post something truly obnoxious and inflammatory, don't imagine for a
- minute that including the words `No Flames' will work. It won't, and
- you'll get exactly what you deserve.
-
- If you're going to flame, you're more likely to get away with it if you can
- cite a fact or maybe a well-known reference. No one is likely to believe
- bald, unsupported assertions.
-
- Be careful about who you choose to insult. Consider not insulting anyone.
-
-
- Asking the Question:
-
- It is a bad idea to post a question and end it with a phrase like `Please
- send email, I don't read this group'. It is a much better idea to
- end the question with `Please send email, if there is sufficient interest
- I'll summarize the results in a later posting. I may miss posted responses
- to this request'.
-
- Answering the Question:
-
- If someone wants to hop up their Yugo, don't tell them to get a Mustang.
- Either be silent, or give them useful advice. If someone wants advice on
- defending a speeding ticket, don't tell them to obey the law next time --
- it's offensive, presumes guilt which is not proven, and doesn't directly
- address the original question. In general, don't post in order to see
- your words in print, and don't post in order to enjoy feeling smug and
- self-righteous.
-
-
- Stale and/or Inflammatory Topics:
-
- Certain topics are considered stale by `old timers'; while discussion of
- them is certainly ok, and new, factual information is welcome, ravings
- about them are extremely tiresome, and may get the person who posts them
- ignored altogether. Some topics are naturally inflammatory; it is
- difficult if not impossible to have meaningful discussion of them. Some
- of these topics include the following:
-
- 1) the 55mph speed limit in the US: Pro and Con
-
- 2) discussions about the morality and legality of the sale and usage of
- radar detectors.
-
- 3) discussions over which radar detector is best.
-
- 4) discussions over what is a sports car (this is one reason why
- rec.autos.sport is not a `sports car' group -- everyone would argue
- about what constitutes a `sports car'.)
-
- 5) disputes over whether or not US Federal law protects the driver's
- right to own and operate a radar detector
-
- 6) `Buy American' discussions
-
- 7) `clever' bumper stickers and personalized license plates
-
- 8) <insert nationality here> cars are terrible
-
- 9) What kind of car did Maxwell Smart drive?
- [when I have a complete, accurate answer it will be added to the
- commonly-asked questions article which is also posted monthly.
- Until then, please don't waste bandwidth on this topic. -- rpw]
-
-
-
- Please direct comments and suggestions about this article to:
-
- welty@cabot.balltown.cma.com
- --
- richard welty 518-393-7228 welty@cabot.balltown.cma.com
- ``Nothing good has ever been reported about the full rotation of
- a race car about either its pitch or roll axis'' -- Carroll Smith
- Xref: bloom-picayune.mit.edu rec.autos:93170 rec.autos.tech:48673 rec.autos.sport:25111 rec.autos.driving:14708 rec.autos.vw:10580 alt.autos.antique:2401 misc.consumers:62205 news.answers:4704
- Path: bloom-picayune.mit.edu!enterpoop.mit.edu!biosci!uwm.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!udel!intercon!psinntp!balltown!welty
- From: welty@cabot.balltown.cma.COM (richard welty)
- Newsgroups: rec.autos,rec.autos.tech,rec.autos.sport,rec.autos.driving,rec.autos.vw,alt.autos.antique,misc.consumers,news.answers
- Subject: rec.autos: Automotive Mailing Lists
- Keywords: Monthly Posting
- Message-ID: <1992Dec20.050103.28338@cabot.balltown.cma.COM>
- Date: 20 Dec 92 05:01:03 GMT
- Reply-To: welty@balltown.cma.com
- Followup-To: rec.autos
- Organization: New York State Institute for Sebastian Cabot Studies
- Lines: 155
- Approved: news-answers-request@MIT.Edu
-
- Archive-Name: rec-autos/part2
-
- Automotive Mailing Lists (Electronic Mail, that is):
-
- [last updated 11/24/92; international harvester, racing fabrication
- technique lists -- rpw]
-
- There are a number of electronic mailing lists on the network devoted to
- various special automotive topics.
-
- To the best of my knowledge, all the lists appearing here have open
- membership policies. It is my policy not to list `closed' mailing lists
- here.
-
- Most mailing lists provide separate addresses for administrative
- queries and for general mail; where separate administrative
- addresses exist, I have listed those below, as the general addresses
- are not appropriate for inquires and requests to be added.
-
- Audi
- (send requests to quattro-request@aries.east.sun.com)
-
- Autocross/Solo
- (send requests to autox-request@hoosier.utah.edu)
-
- BMW
- (send requests to bmw-request@cabot.balltown.cma.com)
-
- British Cars
- (send requests to british-cars-request@hoosier.utah.edu)
-
- Camaro/Firebird (GM F-body)
- (send requests to f-body-request@boogie.EBay.Sun.COM)
-
- Celica (Toyota)
- (proposed list; celica-request@cup.hp.com
- or ...!uunet!cup.hp.com!celica-request)
- Corvettes
- there are two lists; the first is more of a competition oriented
- list, and the second is more general in nature (or so i am told)
-
- Competition:
- (send requests to vettes-request@cimage.com)
- General:
- (send requests to vettes-request@compaq.com)
-
- Datsun/Fairlady Roadsters
- (send requests to datsun-roadsters-request@hoosier.utah.edu)
-
- Dodge Stealth/Mitsubishi 3000GT
- (send requests to stealth-req%jim.uucp@wupost.wustl.edu)
-
- Eclipse/Talon/Laser
- (send requests to diginst!talon-request@radius.com)
-
- Electric Vehicles
- (send requests to info-ev-request@ymir.claremont.edu)
-
- Exotic-Cars
- (send requests to exotic-cars-request@rigel.dfrf.nasa.gov)
-
- Fabrication (race cars)
- (send requests to racefab-request@pms076.pms.ford.com)
-
- International Harvester (discussion of Scouts, pickups, etc.)
- (send requests to ihc-request@balltown.cma.com)
-
- Italian Cars
- (send requests to italian-cars-request@cabot.balltown.cma.com;
- both regular and digest forms available)
-
- Hondas
- (send requests to info-honda-request@cs.ucla.edu)
-
- Hot rods
- (send requests to hotrod-request@dixie.com)
-
- Land Rovers
- (send requests to land-rover-owner-request@stratus.com)
-
- Lotus
- (this list has moved; i know that i should have the
- correct address in here, but i'm swamped. try
- lotus-request@esprit.com)
-
- Mazdas
- (send requests to mazda-list-request@ms.uky.edu)
-
- Merkurs
- (send requests to merkur-request@pcad.UUCP)
-
- Mopar
- (mostly high performance Chrysler, Dodge, Plymouth products.
- send requests to mopar@casbah.acns.nwu.edu)
-
- MR2
- (send requests to mr2-interest-request@validgh.com)
-
- Mustangs
- There are two lists, the first is for Mustangs through 1973,
- the second for Mustangs from 1980 on. nobody cares about
- the Mustang II, so don't ask.
-
- classic:
- (send requests to classic-mustang-request@hpfctjc.fc.hp.com)
- modern:
- (send requests to mustangs-request@cup.hp.com)
-
- Offroad/4X4
- (send requests to uunet!ginosko!wizvax!spg)
-
- Porsches
- (send requests to porschephiles-request@tta.com)
-
- Rally
- (send requests to rally-request@stratus.com)
-
- RX7
- (send requests to jjn@cblpf.ATT.COM)
-
- Saabs
- (send requests to saab@network.mhs.compuserve.com)
-
- Saturn
- (send requests to saturn-request@oar.net)
-
- School (high performance driving schools)
- (send requests to school-request@cabot.balltown.cma.com)
-
- Sentra SE-R, G20, N2000
- (send requests to se-r-request@pencom.com)
-
- Supras
- (send requests to supras-request@vicor.com)
-
- Toyota
- (send requests to toyota-request@quack.sac.ca.us)
-
- Volvos
- (requests to volvo-net-request@me.rochester.edu)
-
- VWs
- (send requests to info-vw-request@ames.arc.nasa.gov; this
- list is gatewayed with rec.autos.vw)
-
- Wheel-to-Wheel Racing
- (forum for race drivers, workers, crew, and wannabes;
- send requests to wheeltowheel-request@abingdon.sun.com)
-
- Z-Cars (Nissan/Datsun)
- (send requests to z-car-request@dixie.com)
- --
- richard welty 518-393-7228 welty@cabot.balltown.cma.com
- ``Nothing good has ever been reported about the full rotation of
- a race car about either its pitch or roll axis'' -- Carroll Smith
- Xref: bloom-picayune.mit.edu rec.autos:93171 rec.autos.tech:48674 rec.autos.sport:25112 rec.autos.driving:14709 rec.autos.vw:10581 alt.autos.antique:2402 news.answers:4705
- Path: bloom-picayune.mit.edu!enterpoop.mit.edu!biosci!uwm.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!udel!intercon!psinntp!balltown!welty
- From: welty@cabot.balltown.cma.COM (richard welty)
- Newsgroups: rec.autos,rec.autos.tech,rec.autos.sport,rec.autos.driving,rec.autos.vw,alt.autos.antique,news.answers
- Subject: rec.autos: the Rec.Autos Archive Server
- Keywords: Monthly Posting
- Message-ID: <1992Dec20.050202.28404@cabot.balltown.cma.COM>
- Date: 20 Dec 92 05:02:02 GMT
- Reply-To: welty@balltown.cma.com
- Followup-To: rec.autos
- Organization: New York State Institute for Sebastian Cabot Studies
- Lines: 10
- Approved: news-answers-request@MIT.Edu
-
- Archive-name: rec-autos/part3
-
- The Automotive Articles Archive Server:
-
- the automotive archive server is in the process of being rehosted,
- and is presently not available.
- --
- richard welty 518-393-7228 welty@cabot.balltown.cma.com
- ``Nothing good has ever been reported about the full rotation of
- a race car about either its pitch or roll axis'' -- Carroll Smith
- Xref: bloom-picayune.mit.edu rec.autos:93172 rec.autos.tech:48675 rec.autos.sport:25113 rec.autos.driving:14710 rec.autos.vw:10582 alt.autos.antique:2403 news.answers:4706
- Path: bloom-picayune.mit.edu!enterpoop.mit.edu!biosci!uwm.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!udel!intercon!psinntp!balltown!welty
- From: welty@cabot.balltown.cma.COM (richard welty)
- Newsgroups: rec.autos,rec.autos.tech,rec.autos.sport,rec.autos.driving,rec.autos.vw,alt.autos.antique,news.answers
- Subject: rec.autos: Frequently Asked Questions
- Keywords: Monthly Posting
- Message-ID: <1992Dec20.050303.28470@cabot.balltown.cma.COM>
- Date: 20 Dec 92 05:03:03 GMT
- Reply-To: welty@balltown.cma.com
- Followup-To: rec.autos
- Organization: New York State Institute for Sebastian Cabot Studies
- Lines: 215
- Approved: news-answers-request@MIT.Edu
-
- Archive-name: rec-autos/part4
-
- [this article is one of a pair of articles containing commonly
- asked automotive questions; the other article contains questions
- of general consumer interest, and is broken out to facilitate
- crossposting to misc.consumers -- rpw]
-
- [last change: 30 september 1992; fix typo in one answer -- rpw]
-
- Commonly Asked Questions
-
- Radar Questions:
-
- Q: Where are radar detectors illegal?
-
- A: In the US, currently Virgina, Connecticut, and the District of
- Columbia prohibit all usage of radar detectors. The Connecticut
- law has been changed, and detectors will be legal in that state
- beginning in October of 1992. New York prohibits their use in
- large trucks. In Canada, they are illegal in Manitoba, Ontario,
- Quebec, Newfoundland and PEI (Prince Edward Island). They
- are apparently are illegal through most, if not all, of Europe.
- Legislation which would make them illegal is pending in many other
- jurisdictions; chances of such legislation passing varies a great deal.
-
- Q: Where are Radar Detector Detectors used? Do they really work?
-
- A: Usage is spreading rapidly; initially they were used only in Canada,
- but now they are appearing in New York and Virginia. It is unsafe
- to assume that they are not in use in Connecticut and D.C.
- They work by detecting a certain frequency radiated by many currently
- available super Het radar detectors; some brands of detector radiate
- more strongly than others, and are thus more likely to be spotted.
- New radar detectors are becoming available which may not be detected
- by the current generation of detector detectors. Note that a
- detector may only be spotted by one of these devices if it is turned
- on.
-
- Q: What is VASCAR? Is it some kind of Radar?
-
- A: VASCAR is nothing more than a fancy stopwatch and time-speed-distance
- computer. It depends on the operator pressing buttons as the target
- vehicle passes landmarks. No radar signals are emitted by a VASCAR
- system.
-
- Q: What is Ka band radar? Where is it used? Should a radar detector be
- able to handle it?
-
- A: Ka band has recently been made available by the FCC for use in the US
- in so-called photo-radar installations. In these installations, a
- low-powered beam is aimed across the road at a 45 degree angle to the
- direction of traffic, and a picture is taken of vehicles which the
- radar unit determines to have been in violation of the speed limit.
- Tickets are mailed to the owner of the vehicle. Because of the low
- power and the 45 degree angle, many people believe that a radar
- detector cannot give reasonable warning of a Ka band radar unit,
- although some manufacturers of radar detectors have added such
- capability anyway. The number of locales where photo-radar is in use
- is limited, and some question the legality of such units. Best advice:
- learn what photo radar units look like, and keep track of where they
- are used (or else, don't speed.)
-
- Q: Do radar jammers work? Are they legal?
-
- A: Quick answer: No, and Not in the USA.
- Detailed answer: Cheap radar jammers do not work well at all.
- Jammers that work are expensive and usually the property of the
- military. Jammers are a major violation of the regulations of the
- Federal Communications Commission of the USA.
-
- Driving technique and Vehicle Dynamics Questions:
-
- Q: What are understeer and oversteer?
-
- A: Understeer and oversteer are terms describing the behaviour of a
- car while cornering near the `limit' (limit of adhesion, that is.)
- Most drivers do not normally drive hard enough for these terms to
- be descriptive of the situations they encounter. Simply put, they
- tell whether the car wants to go straight in a corner (steer `less',
- or `understeer') or it wants to turn more in a corner (`oversteer'.)
- Understeer is commonly designed into most production cars so that
- untrained drivers, inadvertantly traveling too fast, won't get into
- trouble. Understeer may also be induced by using too much throttle
- in a corner. Oversteer is designed into some more performance
- oriented cars; it may be induced by lifting on the throttle (Trailing
- throttle oversteer, or TTO). In extreme cases, lifting on the throttle
- may induce so much oversteer that the car reacts by fishtailing or
- spinning.
-
- Some technical details: in a corner at speed, the tires on the car
- will develop what are called `slip angles'; the slip angle is the
- angular difference between the direction that the car is traveling
- and the direction that the steering wheel is directing the car to
- travel. In understeer, the front wheels have a greater slip angle
- than the rear wheels. In oversteer, the rear wheels have a greater
- slip angle than the front wheels.
-
- Q: What is a rev-matched downshift?
-
- A: When downshifting, the engine must be rotating faster in the lower gear
- than it was in the higher gear. However, during a downshift, normally
- you declutch and lift your foot from the throttle, so the revs drop
- rather than increase. In rev-matched downshift, you blip the throttle
- before re-engaging the clutch so that the engine will already be up to
- the new speed. This results in a much smoother and faster downshift.
-
- Q: What does heel-and-toe mean?
-
- A: Heel-and-toe is a technique used to do a rev-matched downshift while
- braking. This is normally challenging, because you need the right foot
- for both the brake and throttle. It is called heel-and-toe because you
- use one end of the foot on the brake, and the other on the throttle to
- match revs for the downshift. In many modern cars this is a misnomer;
- often you must use the ball of the foot on the brake and the right side
- on the throttle.
-
- Note that some race car drivers will skip the clutch, and just use the
- left foot on the brake and the right foot on the throttle, accomplishing
- the same thing.
-
- Q: What is double-clutch downshifting?
-
- A: While your right foot is doing the above, your left foot can do one of
- three things: nothing, declutch once, or declutch twice. The reason for
- declutching twice is to match the speeds of the two shafts in the
- transmission to the speed of the engine. This is usually coupled with
- rev-matching, so that while the engine is in neutral and the clutch
- engaged, the throttle is blipped and both shafts of the transmission
- speed up.
-
- The procedure is as follows:
- (0) declutch
- (1) move gearshift lever to neutral
- (2) engage clutch
- (3) match revs
- (4) declutch
- (5) move gearshift lever to next lower gear
- (6) engage clutch
-
- This sounds like a lot of work, but with practice it becomes natural.
- The problem that double-clutching solves is normally the function of the
- synchronizers within the gearbox. In transmissions without synchros or
- with very worn synchros, double-clutching makes it much easier to shift.
- Basically, if you double-clutch well, you are not using the synchros at
- all. This is generally unnecessary on street cars with synchros in good
- condition.
-
- Q: What do the numbers for acceleration from 0-60, 1/4 mile, skidpad, and
- slalom times in the Auto Magazines really mean? May they be compared?
-
- A: In short, 1) not as much as the magazines want you to believe, and
- 2) almost never.
-
- In more detail: the acceleration numbers (0-60mph and 1/4 mile times
- in the US) may be vaguely compared as long as they all come from the
- same source. Testing procedures vary so much from magazine to magazine
- that comparing a Road & Track number to a Car & Driver number is quite
- pointless. Keep in mind, too, that the same variation applies from
- driver to driver on the street; the driver is a major (often *the*
- major) part of the equation.
-
- Skidpads vary, and even if they didn't, skidpad figures are really
- only tests of the stickiness of the stock tires; they change radically
- when tire compounds change. DO NOT make any assumptions about the
- comparative handling of, say, two sports sedans based on skidpad numbers.
- This is not to suggest that skidpads are without value, however. Skidpads
- are an excellent educational tool at driving schools. They are simply
- of limited value in the comparison of anything except tires.
-
- Slalom times are slightly more useful; they test some small parts of the
- automobile's transient response. However, they are also heavily influenced
- by the stock rubber on the car, and they do not test many corners of the
- car's envelope. They DO NOT tell you all you need to know before making
- a buying decision. For example, they don't tell you what the rear end
- of the car will do on a road which suddenly goes off-camber. When a car
- has an adjustable suspension, these tests are usually done in the `sport'
- setting, which may be quite unsuitable for daily driving. The list of
- caveats could go on for page after page.
-
- Misc. Questions:
-
- Q: What does <name or acronym> stand for?
-
- A: Here is a list of some of the names which are commonly asked
- about; be careful in soliciting the meanings of other names
- as misinformation abounds on the net. In particular, NEVER
- ask in rec.humor if you want a useful result.
-
- Saab: Svenska Aeroplan A. B.,
- or The Swedish Airplane Corporation
-
- Alfa: Societa Anonima Lombarda Fabbrica Automobili,
- or The Lombardy Automobile Manufacturing Company
-
- Fiat: Fabbrica Italiana di Automobili Torino,
- or The Italian Automobile Manufacturers of Turin
-
- BMW: Bayerische Motoren Werke,
- or Bavarian Motor Works
-
- MG: Morris Garage
-
-
- Q: Does VW own Porsche?
-
- A: No. Porsche is a publicly held company, controlled by the Porsche and
- Piech families. Porsche has extensive business dealings with VW/Audi,
- which causes some confusion. Since currently Porsche is in some
- financial difficulty, there is a possibility that Mercedes or VW may
- be interested in purchasing the company in the near future, but this
- is only speculation at this time.
- --
- richard welty 518-393-7228 welty@cabot.balltown.cma.com
- ``Nothing good has ever been reported about the full rotation of
- a race car about either its pitch or roll axis'' -- Carroll Smith
- Xref: bloom-picayune.mit.edu rec.autos:93173 rec.autos.tech:48676 rec.autos.sport:25114 rec.autos.driving:14711 rec.autos.vw:10584 alt.autos.antique:2404 news.answers:4707
- Path: bloom-picayune.mit.edu!enterpoop.mit.edu!biosci!uwm.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!udel!intercon!psinntp!balltown!welty
- From: welty@cabot.balltown.cma.COM (richard welty)
- Newsgroups: rec.autos,rec.autos.tech,rec.autos.sport,rec.autos.driving,rec.autos.vw,alt.autos.antique,misc.consumer,news.answers
- Subject: rec.autos: Frequently Asked Consumer/Automotive Questions
- Keywords: Monthly Posting
- Message-ID: <1992Dec20.050404.28538@cabot.balltown.cma.COM>
- Date: 20 Dec 92 05:04:04 GMT
- Reply-To: welty@balltown.cma.com
- Followup-To: rec.autos
- Organization: New York State Institute for Sebastian Cabot Studies
- Lines: 471
- Approved: news-answers-request@MIT.Edu
-
- Archive-name: rec-autos/part5
-
- [this article is one of a pair of articles containing commonly
- asked automotive questions; the other article contains questions
- more geared to the automotive enthusiast, and so is not crossposted
- to misc.consumers. this monthly posting is returning to misc.consumers
- after an extended layoff -- rpw]
-
- [changes as of 20 November 1992: comments about absence of
- speed limit and radar detector Q&A in this posting -- rpw]
-
- Commonly Asked Automotive Questions
-
-
- Tire Questions:
-
- Q: What do the funny numbers on the sides of my tires mean?
-
- A: Typically, you will see something like 195/60HR14. the 195 is the
- overall width of the tire in millimeters, the tread is usually
- narrower. The 60 is the `aspect ratio'; it indicates the height of the
- sidewall of the tire relative to the overall width. Our example tire
- has a sidewall height of 0.60 * 195 ~= 117 mm. The 14 is the wheel
- diameter in inches; there are also some special tires called `TRX'
- tires which have three digit metric wheel diameter designations, like
- 390, which is in millimeters. The R means Radial, and the H is a speed
- rating indicating the highest speed at which the tire, when properly
- inflated and carrying an appropriate load, may safely operate. Common
- speed ratings are S (112MPH), T (118MPH), H (130MPH), and V (up to
- 150MPH.)
-
- Recent changes to the method for specifying tire sizes move the speed
- rating to a different part of the designation; you may therefore find
- designations like 195/60R14 85H; the 85 indicates the per-tire load
- associated with the speed rating -- exceeding this load in continuous
- operation at the rated speed is dangerous practice. What follows is
- a table showing a number of `load indices' and corresponding maximum
- per-tire loads:
-
- Load Index 50 51 88 89 112 113 145 149 157
- Max Load (Kg) 190 195 560 580 1120 1150 2900 3250 4125
-
- Note that the usual mass vs. weight confusion occurs in this table.
-
- In some cases, the letters P or LT may be found in front of a tire
- size; the LT designation indicates Light Truck, and the P designation
- indicates Passenger car. If no letter is given, then the application
- of the tire is Passenger car usage. As far as I know, these letters
- only appear in the US market. The LT designation is prinicipally of
- interest to owners of light trucks and other utility vehicles. For
- the owner of a passenger vehicle, there is no meaningful difference
- between a tire with a P designation and one with no designation at
- all.
-
- If the aspect ratio is omitted, it is probably 80, but may be 78.
-
- Tires with an MS (mud/snow) designation may have their speed rating
- reduced by 20 km/h (about 12mph.)
-
- There is an additional set of ratings on tires for temperature,
- traction, and treadwear. Temperature and Traction are graded
- A, B, and C (with A the best and C the worst); treadwear is
- a numeric rating. These values are of limited value, as they
- are assigned somewhat arbitrarily by tire manufacturers and are
- thus not useful in comparing different brands of tires.
-
- Q: My car has tires with a funny size designation: 185/65HR390; can i put
- normal tires on the car?
-
- A: Your tires are called TRX tires; they were devised by Michelin.
- Because of a somewhat different bead design, they are incompatible
- with normal tires; Michelin used a different diameter wheel for them
- so that they could not be mounted on the wrong type wheel (and so that
- more conventional tires could not be mounted on TRX type wheels.)
- You will need to aquire different wheels to put a normal tire on your
- car; it is barely possible to fit normal tires on TRX wheels, and horribly
- dangerous to do so (the tires may simply peel off the rims in a corner,
- or possibly blow out at high speed.) TRX type tires are becoming hard
- to find; in addition to Michelin, Avon makes suitable tires. Goodyear
- has apparently discontinued their line of TRX tires.
-
- Q: Can I rotate radials from side to side, or rotate them only on one side
- of my car?
-
- A: Car and tire manufacturers have differing views on this subject; many
- say that swapping radials between the left and right hand sides of a
- car is now ok (this group includes Michelin and Goodyear); others
- (for example, Pirelli and Nokia) will void warranties if such swapping
- is done. The best advice is to read your tire manual carefully before
- rotating your tires, and stick to the manufacturer's recommendations.
-