I have a 2011 F350 with a Bigfoot 3000 9’11” camper. My camper dry weight is 3100 lbs, my truck max payload is 4000 lbs, so I am maxed out when loaded. I have 265 70R 17 BF Goodrich AT tires. I always have my fronts at 60 PSI and my rears at 70 PSI given the heavy load. I only air down for beach driving in soft sand. I air down to 30PSI on the rear tires and 25PSI on the fronts. You will be amazed where you can go when air down. I tried for the first time a few years ago and was impressed. Try it out when your with another truck sometime just to get the confidence.