Tire pressure on yokohamas A048

[sabajin]

Hi, I have made use of the search button but couldn`t find nothing useful. What tire pressure would you guys recommend for an autocross event with laps lasting 1:15 - 1:30 (current ambient temp is around 60-70).

The car is almost stock except for whiteline rear subframe inserts. I ve been using the car with the stock primacys for about 7 autox events. On the last two i got great results thanks to a imho optimal tire temp pressure (39F - 37R) hot.

Got two 2nd places and top 30 on over 110 cars. Now, last week i used yokohamas A048 but i didnt feel quiet confident with the rear. The front was great, really inmediate response and pointed towards i wanted to place the car.

The rear on the other hand was all lose. Tire temp pressure at the end of the event was 35F - 31R hot. I am thinking about going to 34F and 28-29R. What do you think?

Thanks a lot in advanced!!

[wparsons]

If you were happy at 39F/37R (2 degree difference), and are finding you don't feel comfortable with the rear running 35F/31R (4 degree difference), my first suggestion would be to bring up the hot pressure in the rear closer to the front.

[sabajin]

That is what i thought too. Started 37F - 35R hot and the rear was all over the place, thats why i started to lower the air pressure up to 31. It does make a lot of sense what you say, maybe the front has way more grip than the rear, correct? Ill follow your advice! i apreciate it a lot.

[strat61caster]

Completely different tire and conditions (Dunlop ZII SS) but I'm running 25 cold and ~27-28 psi 'warm' when I get back to my box between runs, some people are up at 40+ psi on the same tire but different size on a different car, this stuff is really all over the board and all you can do is experiment.