Why Do Trailer Tires Have Different Load Capacities When Used for Dually Application

Updated 12/18/2018 | Published 12/17/2018

Question:

Dear Sir, My self Vinay from India, here I attached an catalogue image describing max tyre load Single and Dual, but load of dual is less than the Single, can you please explain me how it will be calculate. If possible please draw a sketch.

asked by: Vinay G

Expert Reply:

You are correct that trailer tires like the Kenda Karrier ST235/85R16 # AM10501 you mentioned feature slightly different maximum loads depending on if they are used as a single tire or in a dual tire application. This particular tire has a 3,960 pound capacity at 110 psi as a single tire and a 3,520 pound limit at 110 psi as a dual tire.

The reason for this is that the load on each tire in a dual tire setup is never the same. The two tires will be worn differently and when the wear is different the diameter for each tire will also be slightly different. When this happens the larger tire will be carrying more load. Also in general the inner tire of a dual tire setup will be responsible for more load because of the crown in roads. Because the shared load will never be the same tire manufacturers will usually put a lower rating (typically 5 to 10 percent less) on their tires when used in a dually setup.

expert reply by: Chris R