What PSI Should I Inflate My Tires To

Published 07/14/2018

Question:

I have a 2015 Rockwood fiftg wheel that runs around 9,000 lbs loaded. The tires are St225/75R15’s and I just replaced the original D rated tires with E rated. The originals had a sidewall rating of 65 psi but the sticker on the side of the trailer said 50 psi. The new tires have a sidewall rating of 80 psi. Do I need that much pressure for a safe ride? I’m about to start a cross country trip and want to be safe.

asked by: Cliff A

Helpful Expert Reply:

Trailer tires should always be inflated to their maximum psi when the tires are cold. Running your tires at anything other than 80 psi will change the capacity of the tire to some unknown amount and can also cause the tire to heat up faster than it should which is what often causes tire failure.

You also need to make sure your wheels are rated up to 80 psi. This is usually dependent on the valve stem. If you need new stems rated up to 80 psi use part # AM20904.

expert reply by: Charles S