Can 15 Inch Trailer Tires Fit On A 15 X 7.5 Inch Wide Trailer Wheel

Updated 02/21/2011 | Published 02/20/2011

Question:

Dear etrailer- I am running 15 X 7.5 aluminum wheels on a dual axle boat trailer, gross weight of 4000 #. The existing bias tires are only designed for 6.0 wheels and I want to replace them. How far can a 6 ply load range C radial be stretched on to a wider wheel? The Kendas I see here are also rated for 6 wheels. Thanks in advance

asked by: Matt G

Expert Reply:

The 15 X 7.5 wheel sounds like a very wide wheel for a trailer. You might want to try and verify that is the correct width. If you check the back of the wheel and in the casting of the wheel it should have the width of the wheel stamped. You can also measure the width of the wheel, but that is easier to do with the tire off of the wheel. The width of the wheel is measured from the inside bead seat across to the other inside bead seat. It does not include the lip of the wheel. I am including a picture that will show where the width is measured on a wheel.

The reason I am questioning the width is because in 15 inch trailer tires the two sizes available, ST205/75-15 and ST225/75-15 are not designed to fit on a 7-1/2 inch wide wheel. The ST205/75-15 tire size will fit a rim width range of 5 inch, 5-1/2 inch, 6 inch, and 6-1/2 inch. The ST225/75-15 tire size will fit a rim width range of 6 inch, 6-1/2 inch, and 7 inch.

The Kenda Karrier ST225/75R15 Radial Trailer Tire - Load Range D, part # AM10256, you have referenced has a recommended wheel width of 6 inches and can also fit a 6-1/2 inch and 7 inch wide wheel.

Trailer tires are not made to be stretched onto a wider wheel. Because of the stronger sidewall construction of a trailer tire, it is made to mount on a narrower wheel to help in handling the weight capacity that the tire is rated for.

expert reply by: Jeff D