What tire pressure will give you the best traction?

[racer_d]

I have found that to dial out some of the inherant understeer, I run 36f/r and often bleed out the rears in an Autocross environment. Ideally, you want the hot pressures to coincide with the tire manufacturers guidelines. These may be hard to find for "street" tires, but for competition tires, its quite easy.

John.. you run PCA events or only SCCA? Not sure if SCCA is running locally this weekend, but Chesapeake PCA is at Ripken on Sunday (Fathers day).

[der Geist]

My first 2 DE's I left the tire pressure at normal 30fr/36rear as I could not find anyone to give me a straight answer. On my 3rd DE the general concensous was standard plus 5 and let the air out as they heat up. I noticed the car getting squirilly (sic) in the rear end towards the end of the day. on my 4th DE with stock +5 lbs I lost control of the car in the 3rd session. I am going back to 32/36 to see what happens. Of course my DE tires are Continental Conti Sport 2 which I am finding out are not considered to be the best tires for the track. I am going to try my Michelins this weekend and see how they do.

[John V]

Originally Posted by der Geist

My first 2 DE's I left the tire pressure at normal 30fr/36rear as I could not find anyone to give me a straight answer. On my 3rd DE the general concensous was standard plus 5 and let the air out as they heat up. I noticed the car getting squirilly (sic) in the rear end towards the end of the day. on my 4th DE with stock +5 lbs I lost control of the car in the 3rd session. I am going back to 32/36 to see what happens. Of course my DE tires are Continental Conti Sport 2 which I am finding out are not considered to be the best tires for the track. I am going to try my Michelins this weekend and see how they do.

It is entirely possible you overheated the rears. If that's the case, a bit more pressure all around might help.

The Boxster is harder on its rear tires than it is on the fronts.

[John V]

Originally Posted by racer_d

I have found that to dial out some of the inherant understeer, I run 36f/r and often bleed out the rears in an Autocross environment. Ideally, you want the hot pressures to coincide with the tire manufacturers guidelines. These may be hard to find for "street" tires, but for competition tires, its quite easy.

John.. you run PCA events or only SCCA? Not sure if SCCA is running locally this weekend, but Chesapeake PCA is at Ripken on Sunday (Fathers day).

BMW club runs on Saturday at Ripken and the SCCA has an event at FedEx on Sunday, so I'm all booked up.

Depending on what tires you're using and what size wheels they're on, you might find you'll go faster with lower pressures. 36 f/r would be much too high for a boxster on V710s, for instance, but for Hoosiers that may be about right. Victoracers and RA-1s require higher pressures as well.