On both my '96 2500 and my '98 3500, a rotation keeps the wear even. I do this every 5K miles at an oil change. My tire guy told me based on the way the mechanicals are setup for the 4x4 RAMs to rotate at lest every 7500 miles. I went 20K on the '96 and the fronts were cupped and the rears were worn in the center because they were over inflated for the weight I was carrying. I got 75K miles on the original tires on the '98. I would think that I was doing something right. Experience is a mother...