[s-cars] One Flat Turns to Four

[Thomas Rodriguez]

The owner's manual for my '95 S6 says all four tires must have the
same rolling radius but that unevenly worn tires is not an issue.  It
also states that tires should be replaced in pairs and the tires with
the deepest tread should be placed on the front of the car.  This
implies that it's ok to have differing tread depth on the front than
on the rear.

Tom
'95 S6

On 5/1/12, Peter Golledge <petergolledge at gmail.com> wrote:
> Brian,
>
> Never understood the "oh the tires must match, danger danger Will
> Robinson" paranoia running around Audi (and Subie) land.  Consider what
> happens to the trans/diffs when you are on track or auto-x, tires are
> constantly spinning a different speeds with high loads.  The 5.7l SBC in
> the LT-1Q get one or more wheels spinning and throwing off rubber in
> tight turns, been doing this for 8 years with the same gearbox/diff
> (both stock Audi 5000TQ).
>
> Now some math, the diff in radius according to your  measurements is
> 4/32, that makes a difference in circumference of ~ 0.4" out of a total
> of 78".  So one extra rotation of the diff every 195 rotations (1200ft),
> folk worry about that, really?
>
> Next winter come out to Colorado and spend a couple of days with our
> Gruppe-Q (http://www.gruppe-q.com/) crazies.  There you can wear down
> those tires on an ice track and give the differentials a real workout
> with some 40 deg slew, lock to lock, full throttle driving. :-)
>
> Cheers
>
> On 4/30/2012 8:38 PM, Brian Pleet wrote:
>> I blew a tire on my 95.5 S6 traveling between Calgary and Vancouver last
>> week. I heard a clunk, my aftermarket tire pressure monitoring system
>> started beeping and I watched the pressure drop. Unfortunately, that
>> stretch of the Trans Canada highway is the worst across the country with
>> hanging wire nets to catch the rocks tumbling off the mountain. I chose
>> to
>> drive on, aware of the price of a ruined tire. Five km later I stopped in
>> a
>> safe place and changes the Blizzak winter tire with one the summer wheels
>> I
>> was transporting.
>>
>> First I'm told you have to replace tires in pairs, to minimize imbalance
>> side to side. I ordered two replacements. Now I'm told that you have to
>> replace the entire set, one for four because the quattro system would be
>> upset by different tire radius. The blown tire was 7/32 tread depth, the
>> other side was 7/32 and the two remaining are 8/32 left out of a starting
>> depth of 11/32.
>>
>> Two or four? Suggestions?
>>
>>
>
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