Recommended Replacement Tire for an Axle That Needs a ST175D/80R13 Size Tire

Question:

The axles on my pontoon trailer list ST175D/80R13 tires. I think the D means to use bias ply tires. Should I substitute radial tires when the tag on the trailer specifically lists that it should use bias ply? Thanks!

asked by: Jeff G

Expert Reply:

The letter that is directly in front of the wheel size is what kind of tire that needs to be used. In your case it is an R which stands for Radial. The D in the tire size that is found on your axle most likely stands for the recommended Load Range as tires do not typically have a letter in that location of the tire size.

Bias tires tend to be used more for off-road use like farming whereas Radial tires are better for highway and road use. The difference between Bias and Radial tires is that Bias tires have a little bit of a rigid sidewall and Radials are built to stay more cool.

With that being said I recommend going with a Radial tire with a Load Range of D (1,610 lbs at 65 psi). One of the most popular options that we have is the Kenda Karrier # AM10210. This is a ST175/80R13 size tire that has a Load Range of D. It has received great reviews from customers and comes with a limited 2-year warranty.

If you are needing to replace your wheels as well then I recommend going with the Karrier mounted on a Galvanized Wheel # AM31994. The Galvanized finish of the wheel gives it superior protection against water than a powder coated finish would. The wheel has a 5 on 4-1/2 inch bolt pattern so you will need to confirm compatibility on that.

I have attached review videos of the tire with and without the wheel for you to check out.

expert reply by: Jon G