This is the first time with a set of these M/T 275/60/15 ET Streets S/S. They are on a GMC S-15 with a 377 Hyd Roller stroker motor with a glide and a 3.70 Ford 9 inch. What is a good air pressure to run them at. I have them at 15 psi. now and as the sun hits them the psi. will go up.