Difference Between 80R13 and 80D13 Tires on Boat Trailer

Updated 04/22/2020 | Published 04/21/2020

Products Featured in This Question

Loadstar ST185/80D13 Bias Trailer Tire - Load Range D

(3847)

$128.22

Kenda Karrier ST185/80R13 Radial Trailer Tire - Load Range D

(2300)

$125.25

Question:

Hello, I have a bought a used boat trailer that I dont believe that I can determine anywhere on it what the correct tires are. I am left to assume and replace the tires with the same that I find on it. However, can you tell me the difference between 80R13 and 80D13 tires? Also, could you give some advice on rating? Thank you and stay safe!

asked by: Jeff

Expert Reply:

Great question! The difference is that the "D" in the 80D13, like the Kenda # AM1ST79, means it is a Bias ply tire where the "R" in the 80R13, like the Kenda # AM10208, means it is a Radial ply tire.

Bias tires are the original trailer tire and do a great job. They have a stiffer sidewall which makes them better for off-road and agricultural trailers. Radials are the "new" kid on the block and are designed more for highway trailer use. They have more flex in the sidewall which helps handling at higher speeds as well as helps to keep them running cooler.

Most people travel on roads with their trailer so Radial is typically the way to go. One other thing to note is that you want to make sure that all of your tires are the same size and the same load range, otherwise you can see some uneven or premature wear. Load range is more or less a standard "weight rating" for a tire. There can be some variances in the actual capacity but it's a decent way to search for weight range.

Attached are review videos on the tires mentioned above as well as a link to our helpful articles on trailer tires and wheels if you want some more insight or helpful tips.

expert reply by: Jon G