What is the Difference Between Radial and Bias Ply Trailer Tires

Updated 04/09/2014 | Published 04/08/2014

Question:

Two axles on the trailer. Im confused about radial vs bias tires. Our boat weighs 4,000#. We do most of our driving on the interstate.

asked by: Dick

Expert Reply:

The main difference between a radial ply and a bias ply tire is how the tire is constructed. The cords inside a bias ply tire run at a 32 degree angle to the direction of travel, and the cords on a radial tire run at a 90 degree angle to the direction of travel, or across the tire from wheel lip to wheel lip.

A radial tire flexes more than a bias tire, giving it better ground contact, traction, stability, and tread wear. A radial tire will normally run cooler than a bias ply tire, especially when the tire is under a load. A tire that runs cooler will last longer.

A bias ply tire has a stiffer sidewall than a radial, a feature that might be useful for off road applications like farm use. At one time radials were more expensive than bias ply tires, but now they are closer in price. This makes radials a much better value.

To determine if one or both types of tires are available for your trailer I would need to know the tire size. I have included a couple of links to our help articles on tires and determining tire size for you.

expert reply by: Michael H