Palting

I use 36/44 on the street, and 32/38 on the track. I drive home from the track with the lower pressures, and can't say that I notice a difference on the street. The C4S does have a tendency to tramline and get skittish due to the sport suspension set up. Once, when had new tires installed, the shop put 32 all around. It seemed smoother on the drive home. I pumped it back up the following day, and it was not as smooth but still smoother than the old. I don't think 32 all around is good for the rears, though.

Lomcevak

I religiously ran 36/44 on my car (18s) and found the rears showing wear patterns suggesting they were overinflated. The fronts were perfect..............

RexracerX

I upped my pressure to 36/40 after bending my 18" rims and impact breaking sidewalls on the smallest potholes @ 32/36. The ride is firmer but my C2 handles much better.

I know I have some allignment issues however, with the higher pressure I don't wear out the inside edges of the front tires like I used to. The rears are wearing nice and even.

jyoteen

I really am able to tell with a 2lb differential. Any lower and the car feels downright dangerous to me. You can tell it wants more air in the tires at 32lbs.

IMHO, the factory wouldn't recommend a specific pressure if they didn't think there was a valid reason for it. I doubt Porsche really cares about tire longevity.

I asked Pobst about track tire pressures and fiddling with them and his response is that the factory engineers know best.

Edit: For a stock/factory setup which I have.

1999Porsche911

I agree with you jyoteen. The car wants to wander with too low of pressure. My tires wear evenly at higher pressures. Frankly, I think it is dangerous to have them less than 36/40 cold. As far as wearing...keep an eye on the tread...it will tell you if you need more or less pressure.

Stevo'99

I have been experimenting with tire pressure. My car feels really balanced at 34/38. I've tried the fronts from 32-38 and the rears from 34-44. This is on fairly new P-zeros and includes dry/smooth/bumpy/gravel/wet conditions. I don't track the car (until they build the new racetrack due by the end of '05) as of yet.