After towing our 34 foot travel trailer, 7500#GVWR earlier this month with my 2021 Ram 1500 Big Horn Crew Cab 4X4, 5.7L eTorque, 3.92 Ratio Axle, OEM Bridgestone Dueler 275/55R20 113T Tires, Air Lift 1000 Coil Spring Air Bags, Fastway e2 800/8,000# Load Leveling Anti Sway Hitch on the Interstate with bad cross winds and lot of semi's, I decided I needed to upgrade my tires and hitch, because the handling on that trip got a little dicey. I had 46 psi in the tires and I had e2 trunnion bars maxed out for lift and sway. The ends of the trunnion knuckles were wallowing out the trunnion head.
I'm having Cooper AT3 LTX LT 275/55R20 120S (E) tires put on it tomorrow. They'll rated 3,085 @80psi, OEM's were rated at 2,535 @44 psi. I didn't want to upsize my tires because I like the pulling power I have now. I also bought a barely used Fastway e2 1200/12,000# WD Hitch for $200 with a minimum tongue weight of 800#, which I easily have. I'm keeping my original tires and rims with only 6,500 miles on them. I found some identical OEM rims, but painted, for $200 w/TPMS sensors to mount the new tires on. I'm planning on putting 65 psi in the new tires when I tow and see how they do I found this website, others may have posted in the past, to calculate how much pressure to put in my new tires when I'm not loaded up and towing. Mine calculated out to be 52 psi, OEM tires were 36 psi on the door post. That website is posted below:
Easy to use tire pressure calculator. Use our tire pressure calculator to calculate the new tire pressure needed when changing tire sizes.
tiresize.com