Just to echo all the other echo’s, tire pressure’s are rated for ply, for mileage, wear characteristics, towing capacity, etc... what they don’t take into consideration are the ride and handling characteristics of the individual vehicle’s that are modded and driven under different extremes etc.... The tires are made to meet government mandates for safety bead seat and sidewall strength as stated. With all that being said They post the tire maximum pressure’s for safety, wear, fuel consumption and tire patch contact. Wheel sizes and rim widths all come into play. The auto manufacturer then chooses what tire is going to go on what vehicle and the engineers set your Tpms. You can run lower pressure’s safely by doing a contact patch to see how much of the tread is hitting, how the ride and handling are and any loss of fuel mileage because it can reduce that also. Too high a pressure will have less contact patch, create a harsher ride and even wear on suspension components as tires are considered part of the vehicle handling dynamic. Use your head and don’t go to low or too high I’ve been through all types of tires on all my builds and I have never run over 45-48 lbs on any of my 4x4’s. In comparison Let’s look at my 12 Power Wagon, it comes stock with a 33x12.50x17 The dealer had over 65lbs in all of them and the truck rode like a steamroller. I Put 37x12.50x17 at about 38-42lbs both are E-rated 8 ply tires. Now if I had put a D-rated 10 ply 37, Or if say I was driving a 3500 those pressure’s would vary also. I would probably start at about 36lbs due to the stiffer ply. I don’t look at the Tpms warning light except to see that I’m maintaining my desired tire pressure’s.