What is the Difference Between Trailer Tire Sizes ST205/75D15 and 205/75R15

Updated 04/06/2016 | Published 04/04/2016

Question:

what is the difference 1n a ST205/75D15 to a 205/75R15

asked by: John R

Expert Reply:

The difference is that the letter D in the first tire size means bias-ply construction and R means radial construction.

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.

The part # TA43ZR that you referenced would be a great option for you as long as your trailer has hubs with a 5 on 5 inch bolt pattern.