Can an ST225/75-15 Trailer Tire be Mounted on a 5 Inch Wide Rim on a 5th Wheel Trailer

Question:

Mine is 03 28foot 5th wheel. want to put ST225/75R15 10 ply tires on it. Current Rim size is 15inch 5/4.5 bolt pattern with a center hub-axle hole at 3.25inch maybe 3.3 dealer sold me a new rim 15inch x 5inch with 5 bolts but the bolt pattern measures 5.5inch and wont fit my hub Have also been told I should NOT put a ST225/75R15 tire on a 5inch rim? How do I know who and/or what to believe?

asked by: J.R. L

Expert Reply:

Any given tire will fit a range of rim widths. The ST225/75-15 tire will fit 6, 6-1/2, and 7 inch rims, but not a 5 inch rim. The tire will not be able to seat properly on the rim and you will not be able to keep air in it or safely use it. As far as who you should believe, our resident tire expert has 30 years in the tire business so I trust his expertise on anything to do with tires/wheels.

For an ST225/75-15 tire on a wheel with a 5 on 4-1/2 bolt pattern we have # AM3S862. This tire has an 8 ply rating (there are no tire and wheel combos with a 10 ply rating in this size). It tire and wheel combo is rated for 2,050 pounds. The tire needs to be inflated to the maximum psi rating as indicated on the tire, 65 psi in this case.

However, the pilot hole in the center of the wheel is 3.19 inches. This would be too small to fit over the hub on your trailer. What tire size is currently on the trailer because that is the size you are going to want to keep. Going to a different size can cause clearance issues and the ride quality of the trailer. Going to a larger size also does not allow you to carry any additional weight.

If you are having blow outs, make sure your tires are always inflated to the max psi as indicated on the tire. Tires are made with a thicker side wall to handle more vertical load and if not inflated all the way they can have excessive heat build up and fail. I have included some FAQ links on tires for you.

expert reply by: Michael H