Trailer Tires are Making Contact with Fenders and Wearing Out the Tires

Question:

How does rim width affect tire width? I currently have 15inch wheels and 225 u5 15 tires. I think the wheel width is more than 6inch though. The current tires are slightly wider than the fender and it appears there is some variability in the contact patch of the tire. Is this caused by rim width? Some have a flat contact patch and some appear more rounded.

asked by: Brett K

Expert Reply:

A tires section width is pretty much finite meaning despite the width of the wheel the tire width will always be basically the same and will be wider than the wheel it is on. This is assuming that you are using a wheel width that is compatible with the tire size.

For a 225/75-15 trailer tire it will fit a 15 x 6 to 15 x 7 wheel. Wheel width is not the overall width. It is measured from bead seat to bead seat where the tire sits. The overall width will be about 1 inch more.

It is possible that the tires are making contact with the fender because:

1) They are too large for that trailer
2) There is a problem with the suspension
3) The trailer is overloaded compressing the suspension all the way

There could be other issues as well but these are the most likely. It does sound like the tires are too large for the trailer since they are wider than the fenders. You may need to go to a 205/75-15 size which is 1.2 inches shorter and about 0.78 inches narrower compared to a 225/75-15. The 205 size fits 15 x 5 to 15 x 6-1/2 inch wheels so you may be able to reuse the wheels.

If you want to go ahead and which to the 205/75-15 tires you can use # TR20515D. This tire is rated for 2,150 pounds at 65 psi. If the capacity is high enough then this could solve the issue barring any problems with the suspension.