Recommended Tire Air Pressure for 10 Ply Rated ST225/75R-15 Trailer Tire

Question:

looking for rim and tire replacement for 2008 25.5 foot Sportsman 5th wheel trailer. GVW 8600lbs. It now has ST 225/R15 8 ply tires on 15x5 5 bolt on 4 1/2 . max tire air pressure 50 pounds. Because we are taking a trip to a area of Canada noted for poor roads i was told to upgrade tires to 10ply. So now i,m confused as i was always told to run ST tires at max air pressure to limit sidewall flex , which in the case of the 10plys is 80 lbs. Now im been told thats not a problem as my trailer isnt that heavy. So i guess my question is are these rims safe at 80 psi? Or is it a none issue bacause the trailer isnt a heavy weight and ill be fine going with the 10 plys at a lower air pressure?

asked by: Dan M

Expert Reply:

First let me begin by saying that a 10 ply rated tire won't necessarily have 10 plies, it'll just be rated as if it did.

In order to maximize the load carrying ability and life of the tire, trailer tires should always remain inflated to the air pressure listed on the tire's sidewall, unlike tires on a passenger vehicle or truck, what would have an acceptable inflation range.

We do offer a 10 ply rated 225/75R-15 tire, part # AM10303 that has a 2830lb capacity (5660lbs per axle) when properly inflated to 80psi. I'd recommend keeping the tires at their recommended pressure.

expert reply by: Mike L