What does the D15 Mean in Tire Size ST205/75-D15

Question:

D15 WHAT IS THE DIFFERENCE BETWEEN D15 and C15 TIRES. ....ST205/75/D15 vs ST205/75/C15

asked by: CALVIN D

Expert Reply:

I think you are confusing the tire size numbers with load range. This size tire is available as a ST205/75-D15 or as a ST205/75-R15. The D indicates that the tire is a diagonal bias ply construction and the R indicates that the tire is a radial tire construction.

Beyond the size and type, there are load ranges for tires. Most trailer tires are load range B, C or D. This number indicates how much weight the tire can bear at a certain inflation pressure.

The tire and wheel combo you were looking at, part # AM3S638, is Load Range C and can bear 1,820 pounds at 50 psi. The radial tire version of this combo, part # AM32409, is also Load Range C with the same weight capacity.

expert reply by: Patrick B