swathdiver
Full Access Member
This is the chart for my pickup truck. It's rear axle rating is 4000 pounds. As you can see, 42 psi gave it a nice cushion and the tire wore well on both of my trucks. Your axle rating is 4,200 pounds and your back half is heavier than a pickup so you'll want a little more air. BFG's website recommended 47 psi for my CC Sierra and 42 psi for my Yukon XL.
Start anywhere in that range and then measure the tread depth on the inside, middle and outside tread with each tire rotation to see how the tires are reacting to the air pressure you've chosen. If they begin to wear down on the outside edges, you need more air. If they begin to wear down in the center, you have too much air in them.
