When I'm running light, which is most of the time, I run 55/45 f/r on my stock 245/75/16 Michelin LTX M&S tires. When I got the truck, it had LTX A/Ts on the back and all four tires were at 80psi. The @#$%^ truck tried to kill me repeatedly on the 65 mile trip home from the dealer. It would not drive in a straight line. Any disturbance on the road would toss it toward the ditch. Lowering the tire pressures helped, but getting rid of the A/Ts helped the most.
I've seen 265's on the 6. 5" wheel, and the owner said that they worked fine, but my money's going toward a set of 8" alloys inside my 265s.
FWIW.
Tom