Just finished a day of Skip Barber school with half a day of hot laps and some autocross.

My two front P Zeros look like someone just unevenly peeled a layer of rubber off the center ridges. The peel only happened to the two center ridges. The rest of the tires and the back tires are fine.

I started the day with 36 psi in front.

Not sure what happened. Anybody experienced the same or can explain?

 

You scrubbed off some rubber, you could have dropped your pressures down, while driving aggressively at events your tires will build up heat and your pressures will increase, keep that in mind.

 

maybe too much air in your tires!?!?

 

I agree, sounds like you were too high pressure. Normally, 32 cold is a good starting point as most tires are best around 40 psi hot. This would be typical at the track, 8-12 psi increase. If you were overinflated, the centers would get the hottest, and you would wear them quickly there.

 

Funny thing is I had run the same tire pressure before in the middle of a hot summer with no problem. Also the rear tires started at 44 psi cold so should have much higher pressure but still fine.

I did slide more today. What pressure should I use?

40 psi hot for all four?

 

44 cold? Wow!!! Way high!

Yes, as a good rule of thumb, 40 psi hot is how tires are typically designed to run for heavy cars like ours. I am surprised you weren't sliding around like hell with pressures that high?

To really know what you are doing, you should get a insertion tire pyrometer (tire thermometer). Here is the best one I know of and the one I have.

http://www.longacreracing.com/catalo...id=188&catid=7

You have to make sure you measure as hot as possible, but this will tell you how you are running. I'll bet that you were at least 20F higher in the centers, probably 30 or more, and this would have told you to drop pressure.

 

Hey Color:

That's a serious looking unit!

Mike

 

I'm an engineer and just love tech toys! The thing even has predictive temperature compensation so you don't need to wait for full temp readings to stabilize. It is fast accurate, and awesome.