Originally Posted by 4x4van
Gotta know the tire make, size/load range of your tires. If you are running the Michelin 235/80R22.5 LRG, then the fronts should be at 80psi, rears at 75psi. However, that front pressure is pretty close (good for 3860), so I would probably bump the fronts up to 85psi. Did you weigh it with you and your wife on board, sitting in the cab?
I am running Michelin XZE 255/70/22.5.
The Michelin RV Tire brochure has the lowest pressure at 80psi.
The 80psi weights are 4190 for single and 3970 for dual.
So at 3800, I am good at 80psi. For the dual, the weight is 3250 (6500 divided by 2). So that should also have 80psi for the rear duals also.