I actually have never noticed this, which is embarrassing, but should I adjust the tire PSI when the truck is loaded up? My tires are rated at 65psi cold. It was set at that when unloaded. However, with our toy hauler and approx. 1000lb of tongue weight, the PSI jumped to 75. Should I air the tires back down to 65?

 

NO. Always adjust tires to desired/max pressure when cool/cold--at ambient temperature.
10psi just by hooking up the trailer doesn't sound right--do you mean after towing it some?
Joe

 

Not a dumb question.

 

Your tires should be rated for 80 PSI, NOT 65. You evidently have load range "D" tires on the truck, and SHOULD NOT be towing anything with a tongue weight of 10,000 pounds. You are running the risk of a blowout if you're loading those tires that heavily.


RON

 

Those are still pretty heavy duty tires.

 

I have nitto terra grapplers in a 305/70r17 size. They are load E rating and have a max 65psi with over 3000lb rating.

So should I adjust the air pressure with the trailer on?

 

I'm thinking Americas tire inflated them according to the 80psi door sticker. However, the front tires were set 65psi.

 

I don't think the door sticker said 80 psi.

 

Tires should be aired to pressures that show about 10% difference between cold and warm. So you check the pressure before driving. PSI reading shows 60PSI. Drive the truck for several miles at HWY speeds. Check the pressure again. PSI reading should not exceed 66PSI. IF the PSI exceeds 10% then you do not have enough pressure when cold. Air up the tire when cold and check again.

Consideration should be given if you want the pressure higher due to loading/trailering but the 10% rule is good for most applications.