Trailer Tire Sizing
The tires on a boat trailer might be labeled: ST175/80D13 C. *ST – These tires are for a trailer (Specialty Tire for trailer use only) *175 – The maximum width of the tire is approximately 175 mm at the widest point. *80 – Indicates the height of the sidewall is 80% of the width (in this case 140 mm
What size tire is ST175 80D13?
We offer both of the trailer tire sizes you mentioned, ST175/80R13 and ST185/80D13. In terms of size they are very close to one another; the ST175/80R13 size measures 24.1-inches in diameter and 6.9-inches wide while the ST185/80D13 size measures 24.4-inches in diameter and 7.2-inches wide.
What does D mean on trailer tire?
The D is the designation for the internal construction of the tire. The D stands for diagonal or bias ply construction. That means the tire body plies inside the tire will crisscross. The 15 is the wheel diameter in inches and the C after the tire size will designate the load range.
What does the R mean on a trailer tire?
The difference between the two trailer tire sizes is that the letter D in the first size you listed ST205/75D15 stands for bias ply and the letter R in the tire size that they put on your vehicle stands for radial.
What is the difference between st175 and st185?
If you go with a smaller 175 tire and wheel combo, it will be about a half inch more narrow, and little over half an inch shorter than the 185. The biggest difference is capacity. The smaller 175 that you referenced has a capacity of 1,360 pounds at 50 psi.
What is the difference between 175 80d13 and 175 80r13?
Expert Reply: The D in 175/80D-13 indicates that it is a bias ply tire where as the R in 175/80r-13 indicates that it is a radial tire. The difference is how the steel belts inside are oriented. Bias ply tires are generally better in off road types of situations.
How tall is a ST175 80d13?
175/80R13 tires have a diameter of 24.0″, a section width of 6.9″, and a wheel diameter of 13″. The circumference is 75.4″ and they have 840 revolutions per mile.
How wide is a 175 trailer tire?
Trailer tires are built with a thicker sidewall to handle more vertical load. A 175 tire will be approximately 6.895 inches wide but they only fit on 4-1/2 to 5-1/2 inch wide wheels.
What’s better load range D or E?
The load index determines how much weight per tire you can handle. D and E is the load range meaning that the D is 8 ply rated with a max psi of 65 and E is 10 ply rated with a max pressure of 80 psi. Like mentioned above, E is better for towing because you can fill the tire with more air pressure.
Which is better D or R tires?
Radial tires run cooler because their steel mesh dissipates heat, which reduces the chance of a blowout and adds to the life of the tire. Radial tires have a wider footprint, which spreads out tread wear and also adds to the life of the tire. Radial tires are more resistant to punctures.
Can I mix R and D tires?
Expert Reply: It’s fine to use a radial-type tire as a spare (a tire with “r” in its size code) with a trailer that has Bias ply “d” tires but for a short distance in the event of a flat tire. But mixing tires is not recommended for everyday use because their internal construction is different.
What does ST205 75R15 mean?
This number indicates that your tire has a width of 205 millimeters. 75. This number means that your tire has an aspect ratio of 75%. In other words, your tire’s sidewall height (from the edge of the rim to the tire’s tread) is 75% of the width. In this case, the sidewall height works out to be 153 millimeters.
Can I put radial tires on my trailer?
Yes, you can use radial tires on a trailer as long as they are trailer tires. Trailer tires will have ST in front of the size. Radial indicates which way the belts run in the tire.
What is the difference between ST205 75R15 and ST225 75R15?
Expert Reply: An ST205/75R15 tire size like you have now will have a section width of 8.1 inches and overall diameter of 27.3 inches. An ST225/75R15, # AM10256, will have a section width of 8.9 inches and overall diameter of 28.4 inches. So the larger size is 0.8 inches wider and 1.1 inches taller.
