Recommended Replacement Trailer Tires for Boat Trailer with P185/80R13 Tires

Updated 03/22/2018 | Published 03/21/2018

Products Featured in This Question

Karrier KR03 ST175/80R13 Radial Trailer Tire - Load Range D

(2500)

$104.94

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

(4005)

$101.56

Question:

Have P185/80R13 on boat trailer. Can and what is the difference with st185/80R13? Single axle trailer if that matters any. 16ft boat

asked by: Brian H

Expert Reply:

The P in front of the tire size 185/80R13 stands for "passenger" and is for use on an automobile. The ST in front of the ST185/80R13 you asked about stands for "special trailer" and is what we recommend for all trailer applications. The tire is made differently with thicker and stiffer side walls for trailer use. For the ST185/80-13, we only have a bias ply tire # AM1ST79. It is rated for 1,710 lbs at 65 psi and speeds up to 81 mph.

We only have the ST175/80R13 size in a radial tire. I recommend the Karrier ST175/80R13 Radial Trailer Tire - Load Range D # AM10210 rated for 1,610 lbs at 65 psi and speeds up to 81 mph. This tire will be 0.4 inches shorter in diameter and 0.2 inches thinner in width than your previous size tire.

Either will work well on a boat trailer. Radials just run a little cooler than bias ply tires. I've attached an article to assist.

expert reply by: Jason S