What psi should I run my 33" Mud Grapplers at?

 

???

 

40-45 is your best bet. IF you tow or haul allot then you might want to bump up to 50 in the rear.

 

WRONG... i'm running 20-25psi in mine. Higher air pressure equals ****ty ride and bad handling

 

20 psi is way too low. You are killing your fuel millage, and I am willing to bet the truck sways around quite a bit. You are also heating the hell out of the tires being so under inflated.

The CEO's 2010 has 37x13.5s and at 45 psi it rides perfect. I would never let a truck leave the shop with less then 35 psi in the tires. Only time I would is if it were a jeep on 35s or bigger. Then you can get away with 20-25 because it is so light and the tires are so big.