I was told to let some air out, but noone really explained to me how to know what the best pressure is and when to cool down. Would you be so kind as to share your knowledge?

 

I have Michelin PS2s in stock Z06 sizes. They are very tricky on the track but they take the abuse well compared to (3 yr old) goodyear supercars.

Basically, I started with high pressures, as soon as we realized I have traction issues in the rear, we would pull off and let 1-1.5 psi out in the rear.

I would wait a bit, go back. At some point, the rear would start getting swingy again so we would time how long it took, pull off and let another psi or two out. The goal was to have a stable car for as long as I am comfortable lapping (which is about 20 minutes for me), then take another 1/2 psi out and that was it. I settled on about 27.5psi in the rear (measured cold, quite far from the original 32!). I could take more air out the rear and get even more stability for a longer session but I wanted to minimize the wear. The bottom line is that if your rear starts getting funky after a few laps, you have too much pressure there.

I took a little out of the fronts too, since I had some funky turn-in responses at first, but not nearly as much (went down to 31.5psi from original 34, all numbers cold). The idea with the fronts is to have just enough "extra" pressure to avoid wearing off the top of the sidewall and chunking the thread on the outside (my goodyear sc's had problems with this). This also depends on alignment (i have factory spec alignment) and, to a lesser degree, on the age of the tire. Good news about the michelins is that the sidewall/surface edge is rounded and even the street alignment is easy on it.

Looking at your first photo, I'd say you need more pressure in the front (or maybe another look at your alignment), even my supercars were not as bad as this after lapping.

 

Ok, I get the picture. So, since most of that tire damage took place after I reduced pressure, that would be an indication that I may have taken out too much(for the front)? I started with 40 all around this time and it was definitely slippery in the rear. I dropped to 36 all around for the last two sessions, when the damage started showing. I'll start with 38 front and 36 rear next time and drop 1psi at a time if it gets slippery in the rear.

Thanks!