Can a ST205/75R15 Trailer Tire be Replaced by a ST205/75D15
Updated 05/13/2015 | Published 05/12/2015
Question:
Can you replace st205/75r15 with a st205/75d15? Thanks
asked by: Bryan
Expert Reply:
The difference between the two tire sizes you mentioned is the construction of the tires. The R in the ST205/75R15 indicates that the tire is a radial. The D in the ST205/75D15 indicates that it is a bias-ply.
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.
You can run either style on your trailer, but since they will flex differently you will want to stick to either one of the other for all the wheels on your trailer. Dimensional the two sizes you mentioned are exactly the same so the two would be compatible easily from that point of view.
