Why Does Trailer Tire Have Lower Weight Capacity When Used in Dually Setup

Updated 04/10/2019 | Published 04/09/2019

Question:

I was looking at my trailer tires for wear and was surprised to see an addendum to the load rating. A tire that read 1750lbs @50psi had a rating of 1560lbs when on a dual axle. What is the reasoning for this/ What is the general of derating? thanks in advance for your time.

asked by: Stephen

Expert Reply:

This is a really good question that has come up before. I spoke with our local tire guru here at etrailer about this a while back and he offered the following explanation for the difference in tire capacity when a tire is used as a dually or single wheel setup:

The load on each tire in a dual tire system is never the same. Tires can be worn differently, if wear is different the overall diameter will be different and the larger tire will carry more load. Also the inner tire can be more loaded than the outer because of the crown in the road. The loads shared by the dual tires are different from each other.

Because of that they put a lower rating (usually 5 to 10 percent less) on the tires when used in a dually setup.

expert reply by: Jameson C