On my 280 I run 60 lbs front and rear. I had 85- 90lbs in it when I first bought the coach, and it always rode way too hard. I checked my gm manual and the airstream one and both said 55- 65lbs.
Since running at 60 I have improved the ride, and seen no more wear than before. My tires are the standard radial goodyears.
Also- when I drove it home the first time after purchase, the tires were too highly inflated, the airbags were underinflated. Changing that and redoing the rear shocks made a terrific difference in the ride. I also refer you to this thread;
http://www.airforums.com/forum...=tire+pressure