When Choosing Trailer Fenders Do You Go by Wheel Diameter or Tire Diameter

Updated 08/02/2017 | Published 07/31/2017

Question:

My trailer is a homemade DIY that came with my wifes Mini Bass I boat, and the fenders need to be replaced. The wheels are about 13 inches diameter, but the tire is about 20 inches diameter. Will this fender work for that?

asked by: Charles W

Helpful Expert Reply:

When talking about tires if you hear 12 inch, or 16 inch, that is in reference to the wheel diameter where the tire sits on the wheel. So for fenders you will want to look at models based on wheel size and not tire diameter.

Wheel diameter is not measured as an overall diameter. Instead it is the diameter where the tire makes contact with the wheel. As such the wheel diameter that gets listed is always less than the overall diameter. So if you are at 13 inches overall you likely have 12 inch tires. But the easy way to tell is to look at the tire size on the sidewall of the tire. For example if it says 4.80-12 the 12 in that size indicates the wheel diameter. If it says 175/80-13 the wheel diameter is 13 inches.

The Fulton Single Axle Trailer Fender with Top and Side Steps - Black Plastic - 14" Wheels Item # F008584 for example fits 14 inch wheels.

I have included a link to the fender main page for you. Just select the wheel size to see the options. We have options for 8 inch to 16-1/2 inch wheels.

expert reply by: Michael H