I have a 2001 Super Crew with 3" body lift and am running Nitto Terra Grapplers (305/55/20). Right now the tire pressure is about 40 psi, and on the sidewall of the tire, they say no more than 65 psi. These tires are load range: E. For my truck what would be the best tire pressure for normal driving (i.e. little or no off road use, besides gravel roads/playing in deep snow). My father is a mechanic and he said I would be ok to go up to 50 psi, what do you guys think?

 

I would run those at about 45. 40 is a bit low. If those were a LR E with a max of 80, I would agree with your father, run that type at 50, but since your max is 65, I would run them at 45. At that you should not have to add any for any load you carry up to the posted weight limits of your vehicle.

 

I think it mostly depends on your load and what your towing. I have the Mickey Thompson MTZs in load range E, max 80 psi. I contacted Mickey Thompson and asked them what they recommended I run them at and they told me to start at 60 and adjust from there. Well I started at 50 and ended up wearing out the center of the tread faster than the outside of the tread. I dropped the pressure down to 40 and now am runing closer to 37. That's on my 02 Expedition. The ride is much nicer too. If you're hauling alot then yeah 50 is probably a good psi to run them.