Replacement Tire and Wheel Recommendation for 35 Year Old Trailer With ST175/80D13 Tires

Question:

I inherited a boat and trailer that Im going to restore. T want to replace, ideally, is replace the rims and tires. But they are 35 years old. So I need help on what to do. Here are the specs: 1. The lug nut hole pattern is 4 on 4. 2. The tire size is ST175/80D13 3. The pilot hole is 2 7/16. 4. The rim diameter is 14 1/4 I dont know how a 13inch tire is on a 14inch rim? The axel diameter is slightly smaller that the pilot hole on the rim. There is a collar at the back of the hub where the rim slips up on to. Meaning that the pilot hole is a bit larger in diameter than the actual axel. Please let me know what you would recommend and thanks for the help.

asked by: Duane E

Expert Reply:

Even though your trailer is 35 years old, tire sizing has not changed. The Kenda ST175/80D13 Bias Trailer Tire # AM3S120 is the correct tire for your trailer.

The 13 inch measurement comes from the diameter distance on the inside of the tire. The outside of the rim will measure approximately 14 inches because the tire fits inside of the rim/wheel. I went out to our warehouse and measured the # AM3S120 that you referenced and the outside diameter is 14 inches, however it fits a 13 inch tire. In the tri-set of pictures I have attached, I have the dimensions noted as well as where to take the measurements from.

The Kenda # AM3S120 that you referenced is a 4 on 4 bolt pattern and has a measurement of 2-3/4 inches from center to center. The pilot hole size is 2.65 inches which is pretty close to the 2-7/16 inches that you measured on yours. The outside rim diameter is 14 inches.

Axles that are 2-3/8 inch in diameter will typically have a 3500 lb weight rating. These tires have an individual weight rating capacity of 1360 lbs at 50 psi, (or 2720 lbs for the pair). You will want to verify your fully loaded weight of your trailer to ensure you are not overloading the tire capacity.

expert reply by: Lori W