Dennis
1999 Tit. Silver M3

I am glad you brought up the UUC link. I agree these are fundamental principals of chassis tuning. What the others have described is inconsistent with these principals. There must be other contributing factors to the others describing what happens with understeer/oversteer versus tire pressures.

If you want to minimize understeer, you should have higher pressures in the front and lower in the rear. I set my car up for the track this way and it works. BMW wants understeer in the car, that is why they say to put 30-32 psi in front and 35 psi in the rears (owners manual and door jam). To minimize understeer, make the fronts higher and rears less.

On the track with Kumhos, I use 30f/28r cold and they go up 10-12 psi when hot. I only needed 2 psi more in front to minimize understeer.

With Yok A032R, 31 psi cold in front and 27 psi cold in rear. With agressive track use they will go up 8-10 psi hot to say 40-41 front and about 37 rear. I start with 4 psi higher in front to minimize the heavy understeer the M3 exhibits. When hot the difference is say about 3 psi.

These are actually real world experiences and it indicates that the fundamental principals are valid as indicated by dqm3 and the URL at the UUC website.

At the track I talked to people with higher pressures in the rear than the front. I told them to change with about 2-4 psi higher in the fronts. They tried it and could not believe how much more neutral the car handled. One individual commented how this helped to greatly improve his lap times.

I agree with dqm3, books and driving schools are not teaching incorrect chassis tuning principals. Some individuals have a misunderstanding of basic principals. I have encountered individuals like that at the track, we experimented and we went out and proved them wrong. Nothing speaks louder than showing results on the track versus debating it verbally.

Not just opinions, but facts of life.

Brad Devendorf
1997 M3 Coupe