It depend on what tire size & it’s load rating and wheel diameter x width you have on the truck.I was going to reprogram the TPMS pressures to lower pressure in the rear but didn't think about the front.
How low would you go?
For stock size load E tires, probably in 50’s psi. You need to air them down and go from there, just like you will after a new set of oversized mudders installed on your Jeep.
Bigger tires, lower air pressure. Dumb wide tire on narrow wheel, even more lower air pressure. Always remember this; bigger tires = more surface area in contact on ground, therefore less air pressure needed to support the weight. PSI=pound per in^2. It’s all about to get full contact to ground shoulder to shoulder.
My XJ with 36x13.5R15 IROK BIAS on 15x8 wheels; approx 7-8 psi on street
My truck (SRW) with 315/70R17 load E tires (max inflation 65 psi) on 17x8 oem wheels; ~35 psi unloaded (~7,500lbs) all around.