I have a 996 cab with 19 HRE 545r (235 and 275 tires), and will participate in an PCA autocross event in Sunrise Fl, on Aug, 28th.

What tire pressure should I use???

 

Use the stock factory settings if you'll be running the 19" wheels. There's not enough sidewall to gaurd against damage. I used to run 36/42 on my '03 with 19" wheels.

 

at first I did not have enough pressure in the tires and could feel the tires just hugging the asphalt. Then during our lunch break I inflated the tires to 36 and 42 and it made a huge difference. I am going to look for 18" wheels for the track. Thanks

 

Trust me, with the 18's the car is going to be so much better on the track. On the street, I never noticed the difference between the 18's and the 19's, but on the track it was a whole different story. That's why on my turbo S, I'm sticking to 18's.