I think that I'm now using the tire pressure that Yokohama would prefer I use. And now my lap times suck with 32F and 38R. 996 with 18" 285/35 and 225/40's.

I got some pretty fast times out of my first set of AD07's. I attempted to set their pressure by monitoring how far towards the sidewall they abraded. My reference was a line that ran the circumfrence of the tire sidewall about 5mm beyond where the tread ended. So I was definately on the sidewall, but only a little. That had me at 28F 34R.

But there are also some little arrows at the corner of the tread pattern. I read somewhere that the little arrows identified where Yoko expects the abrasion limit to be. I'm now on a new set of AD07's. In order to get the abrasion limit at where those little arrows are, I have to go up to 32F and 38R. And now I'm 5sec/lap slow.

Questions:
1) In general terms is abrading 5mm down the sidewall unacceptable?
2) AD07 users what cold tire pressures are you using? How did you arrive at that pressure?
3) Should I focus on the clock on not on monitoring the abrasion line?

 

I am running 40psi hot.

 

Joe, just to doublecheck I understand...you're saying that you run AD07's and you run 40 psi hot BOTH front and rear?

 

correct.

 

Not a P Car but a data point. E46 M3 285/30 18's ft/rear 38 psi hot. Pressures were set by pyrometer.

Peter