EB, I used to run 80# in rear of my 96 2500, then would deflate to 55# when empty, never did get over 60-75K on set of tires. When I got my 00 dually, went to 60# all around, got 79K out of OEM's, then went to Michelin's from Sams club and got 106K, had them rotated every 8 to 10K. I just serviced my trk. , and went to 60# all around, going to try that for a while. I was really surprised they warrantied my tires, I don't think I ever got warranty on OEM's before.