Tires- 3500 dodge truck

06 Dodge Ram 3500. Just put my third set of Michelin LTs on. I got 70K out of the first set but only 65K out of the second. Of course the second set I put 16,000 miles towing at or just over my rating on some pretty rugged roads through a lot of Northern Canada and Alaska, so I can't really complain. I wore the shoulders thin on the back tires but I can't really put that on the tires. Miser that I am I would have squeaked out my last 5,000 miles on them anyway but I was getting ready to take off on anther trip so my prudence trumped my cheapness.