Can I replace an ST205-75-R15 C tire with D or better tire, or do I need to replace the wheel as well and how would I determine compatibility? Thank you
asked by: Gayle B
A load range D tire in the 205/75-15 size is not available. You would have to go up in size in order to get a load range D tire. Your existing tires have a width of 7.7 to 8.1 inches and a diameter of 27.4 inches. They fit on 15 by 5-1/2 inch wheels.
The next closest size with a load range D tire is 225/75-15. These tires range in width from 8.4 inches to 8.9 inches and could have a diameter between 28.1 and 28.4 inches. They fit on 15 inch by 6 inch rims so new rims would be required. You will need to measure the trailer to determine if the wider and taller 225/75-15 tire will fit. The new size will be 1-1/4 inches wider (max) and 1 inch taller (max).
You will also need to measure the bolt pattern of your wheels. I have included a link to an FAQ article that explains how to measure a trailer wheel for bolt pattern. As long as it is 5 on 4-1/2 bolt pattern , AND you have clearance for the larger size, you can replace your existing tires and wheels. I do not have a wider wheel if you have a 5 on 5 inch bolt pattern. For a 5 on 4-1/2 pattern with a 225/75-15 tire, I recommend # AM3S862.
I have included a link to an FAQ article on measuring a trailer tire for reference.