Re: Re: RE: Need to confirm rumors about tires on 4x4's

From: mrdancer (mrdancer@camalott.com)
Date: Tue Feb 16 1999 - 22:19:21 EST


Actually, the correct term is "tire pyrometer". I did a web search on
AltaVista and got 58 returns. Went to the first one and they had one listed
for $348 (OUCH!!) - it's a race piece with 10-number memory, etc. Maybe a
specialty shop would rent them out, or maybe you can rent or borrow one at a
local racetrack. For just checking tire pressures, the procedure is pretty
simple. If you want to do some more extensive chassis tuning, read on:

Some race car builders (at least chassis tuners) consider the tire pyrometer
to be the single most valuable tool available to set up a race car or hi-po
street car. Some of the things you can measure with just this tool are:
correct tire pressure, handling balance, correct static camber, correct
toe-in/toe-out, if car is being over-driven for the tire tread compound, if
car is being driven at the limits, even if rim width is too narrow for the
tire!

For optimum results, you need to know what temp your tires should be running
(you'll probably have to get this from the manufacturer or tire engineer) -
most tires run between 165 and 250 degrees F. For all-out tests, cars are
usually run at max. g on the skidpad and temps are taken on outside tires,
then car is run opposite direction on skidpad and temps taken on those
outside tires.

Examples: If tires too hot, tread compound is too soft for track
conditions; front tires too hot, understeer or front tire pressures too low;
rear tires too hot, oversteer or rear tire pressures too low; inside edges
too hot, too much negative camber, too much toe-out; outside edges too hot,
too little negative camber, too little toe-out, too much toe-in, wheel too
narrow for tire; center too hot, tire pressure too high; edges too hot, tire
pressure too low; all tires too cold, tread compound too hard for track;
front tires too cold, not enough load on front; rear tires too cold, not
enough load on rear..........

-----Original Message-----
From: fawcett@uism.bu.edu <fawcett@uism.bu.edu>
To: dakota-truck@buffnet.net <dakota-truck@buffnet.net>
Date: Tuesday, February 16, 1999 8:40 PM
Subject: Re: DML: Re: RE: Need to confirm rumors about tires on 4x4's

>Wow! That's cool... I like solutions with no guess work! I almost hate
>to ask what one of these gizmos cost and where you find one but... how
>much/where? :)
>
>T.
>_____________________________ Reply Separator
_________________________________
>Subject: DML: Re: RE: Need to confirm rumors about tires on 4x4's!
>Author: <dakota-truck@buffnet.net> at smtpout
>Date: 2/16/99 7:52 PM
>
>
>The BEST way to determine needed tire pressure is to invest in a good tire
>thermometer (the kind that pokes into the tread). After running the truck,
>you take temps on the outside edge, inside edge, and center of the tire
>tread. Temps should be even across the tread. If it's higher in the
center
>your air pressure is too high - if it's lower in the center your air
>pressure is too low. If it's higher or lower on one edge of the tire, then
>you have uneven loading on the tire, either from incorrect alignment or
poor
>tire fit.
>
>-----Original Message-----
>From: Wayne T. Schultz <rimfax@email.msn.com>
>To: dakota-truck@buffnet.net <dakota-truck@buffnet.net>
>Date: Tuesday, February 16, 1999 4:35 PM
>Subject: DML: RE: Need to confirm rumors about tires on 4x4's!
>
>
>>The tires are too wide for the wheels (10.5 inch wide tires on an 8inch
>wide
>>rim). If you go with the factory recommended air pressures your front
>tires
>>will wear on the outsides and your rear tires will wear in the center. If
>>you adjust your tire pressures to 28-30 psi rear and 38-40psi front you
>will
>>wear your tires evenly.
>>
>>Also you will be able to avoid a lot of unnecessary rear tire spin, that
>>everyone has been talking about.
>>
>>You can verify the wear (since you have new tires) by looking to see where
>>the little nubs on your new tires wear off.
>>
>>Beware what the dealer tells you. Notice: that in all the literature that
>>comes with your truck, nowhere is there any indication of what your tire
>>pressures should be for the 31x10.5 tires.
>>I just got a 99 Dakota Sport + CC 4x4 last Wednesday and have loved it
>>since.
>>
>>While having the dealership look at the vehicle for some visual oddities,
I
>>was
>>informed that I needed to have the tires rotated every 3000 miles in order
>>to
>>prevent severe cupping on them. I was told by the service manager that
>this
>>has
>>been a problem with Dodge trucks ever since they came out.
>>
>>Can someone confirm/deny this? I thought that cupping was caused only by
>>tire
>>imbalance?!?!
>>
>>Thanks!
>>
>>Chris
>>
>>My comments do not represent my company.
>>
>>
>>
>>
>
>



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