My tire pressures are based on even wear, and nothing else. On small cars from 2000-2500 lbs I ran pressures of 32 front, and 30 rear. On larger cars like a Regal or Gran Prix I run 35 front, and 33 rear. On my Envoy, and all three of my GM 1/2 pickups I run/ran 39 front, and 36 rear. I have Milton tread depth gages, and a Slime digital pressure gage. Frequent rotation is helpful, and I think it becomes more critical on the wider tires.