I've been trying to find the correct air pressure to run in my tires. I have the Nitto Terra Grapplers 295/70/17 on a 17x8 rim. Hopefully someone is running the same tire that can give me some insight...... All i know, is sometimes the tires ride better with less air, but I don't want them to wear fast either. Any help would be greatly appreciated.

 

Per the web site, those are a load range D with a max of 65. Run them at 45. Do not go lower than about 42. 45 would be right for anything the truck is rated to, although if towing something heavy, you might want to bump them up a little to help with sidewall flex.

 

Look at the sidewall of the tire, you should see a "max PSI", if it's actually 65psi max, then run it anywhere between 45-50psi. I have 35x12.5r20 Toyo MTs that have 65psi max, and I run them at 50psi. Personally, I haven't noticed any decrease in ride quality, if anything the truck feels more responsive on pavement. They were previously inflated to 42psi, but with 50psi my mileage went up a about 1 mpg as well! :P

 

Yea, I was running them at 40, but man they beat me to death. I've done had all my suspension components checked out. I've had this setup balanced about 5 different times and it seems like nobody can get them right. The other night I took them down to 36 and it seems like they ride a lot better, but like I said before I don't want to risk wearing them quicker. I'm begining to think I might have a set of bad wheels

 

Running a low pressure risks more than just tire wear. Too low a pressure causes tires to build up heat, especially at highway speeds. This can cause blowouts or tread separation. Yes they will be harsher, they are a load range D. If you were used to a P series tire on there before, you definitely will notice the difference. But you will also notice a big difference in cornering and overall handling, for the better.

 

I've always had great luck with 40psi in truck tires.