[Fot] Fwd: Hoosier R6 tire pressures

[Bill Babcock]

Oops, too long again. 

Begin forwarded message:

> From: Bill Babcock <billb at bnj.com>
> The only way to get it right is tire temperatures. Honestly, I don't understand why people ask "what tire pressure are you using". You might as well ask "what size pants are you wearing". A hundred pounds of total vehicle weight difference makes a tire pressure difference that's worth significant time on a race track and significant accelerated wear on tires. If you don't have a real tire pyrometer and test your temps then you are wasting money on good tires. 
> 
> Peyote hasn't worn out a set of tires in recent memory. They just heat cycle to the point that I'm losing time. I see racers with light cars with the center worn out of their tires and the edges still treaded. Overinflation, pure and simple. We don't have 400 horsepower and our cars don't weigh 2400 pounds--our tires shouldn't wear out from racing.  If an overinflated tire makes your car handle better it's because your camber is wrong. 
> 
> Chris, the engineer you were talking to is full of beans. If you have a 50 degree F difference between inside and outside it's either because the reading was taken after a long straight or the camber is wrong. Do the measurements on a skid pad and you can get the inside to outside measurement within 10F. Unless you are running full radial slicks I bet that won't be at 4.5 degrees. You MAY, however, be able to go faster on some tracks with excess camber just because it puts less tire on the ground down the straights. Overinflation does the same thing. Not the fast way around corners though. 
> 
> On Sep 9, 2010, at 8:08 AM, Jason Ostrowski wrote:
> 
>> Thanks for all that info guys. Ive been using up a set of fronts in about
>> 100 laps on my gt6. Granted, I assume that my street t.d.'s are a little
>> different... but what all this seems to be pointing to is that maybe I
>> should drop the starting pressure from 27 a few pounds as my car is about
>> 200-300 pounds lighter than your TR's. I think they rise about 8-10 pounds
>> when hot but I feel like I should be getting a little more life out of the
>> tires. Am I correct in thinking that a little less pressure will promote
>> longevity? I'm not even going as fast as you guys....YET.
>> 
>> Jason Ostrowski
>> Friendly Ghost Racing GT6
>> On Thu, Sep 9, 2010 at 1:20 AM, MadMarx <tr4racing at googlemail.com> wrote:
>> 
>>> A race engineer of a Porsche team said to me that the spread of temperature
>>> on the tires, measured from outside to inside, should not exceed more than
>>> 60F.
>>> 50-60F is the optimum for racing.
>>> 
>>> Cheers
>>> Chris (who is running 4.5 degree at front)