On the rears 285/30/18

I have them at 30-35 psi but Champion suggests 40-45 psi???

and what about the fronts???
I live in hot Florida so should this affect my tire pressure decision?

 

Jeru there is a lot of debate about this. You can read my post at flat-6 and renntech. For me, after some testing in the hot Spain, and with the same 18 wheels and 225/285 I run 32 psi in the front and 36 in the rear, which gives hot a bit less than factory recomendation of 36/44.

 

Check the inside of the fuel door. It will give you porsche's recommended psi. Unless you have your own comfort zone, then its up to you

 

I think champion is crazy-to run the backs at a cold temp of 40 is way to much in my opinion for a hot climate. The car will far exceed 44, stick with the temps carlos gave.

 

That was Antonio from Spain

 

Here is what I run,
Street: 36/44 cold
Track: 34/39 cold (usually works out to 36/44 hot)

FWIW '99GT3 street specs are 34/39 cold.

 

I run at track 31 / 35 cold which goes to 35 / 40 hot. That works best with my Contis. On street, I run 35 / 40 cold for better tire wear.

 

Cold Pirelli's, but it is for a C4S. Standard pressures are way to harsh. The tech at my dealership told me 33/39. A PCA instructor told me 34/40.