Weight and Safety Tip | Dual Tires

By Jim Koca #86367, Escapees RVers’
Boot Camp Instructor

All drivers, especially RVers, should be aware that the air pressure is what carries the load placed upon a tire.

A large number of RVs have dual tires for the drive wheels and, as an accident investigator, I have found that many of these dual tires were not matched to the correct height or circumference. Upon closer inspection, I would find one tire had more tread than the other.

Tires that are bolted together must have the same circumference in order to carry weight equally as the tires roll down the roadway. The taller tire will carry more, or sometimes all, of the weight on that side of the vehicle. This problem will cause the taller tire to be overloaded and exceed its carrying capacity. When this happens, a tire can fail and possibly cause a blowout and even an accident.

When purchasing tires for the drive axle, they should be bought in pairs. Major tire manufacturers recommend that the maximum difference between the diameters of the dual tires does not exceed ¼ inch or a difference in circumference of ¾ inch. In addition, the difference in tread depth between the two tires should not exceed 4/32 inch. Mismatched dual tires can cause uneven wear patterns, rapid tire wear and the possibility of a tire failure.