Capacity of 5.3 x 12 Tires and Wheels Compared to 175/80R13 Tires and Wheels on a Boat Trailer

Updated 08/12/2010 | Published 08/11/2010

Products Featured in This Question

Karrier ST175/80R13 Radial Trailer Tire with 13" White Wheel - 5 on 4-1/2 - Load Range D

(1575)

$149.74

Kenda K353 Bias Trailer Tire - 5.30-12 - Load Range D

(3888)

$61.22

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

(2348)

$104.94

Question:

I feel my boat trailer has too small of wheels on it 5.3 x 12. Dry weight of boat, motor and trailer is 2250lbs. I was thinking of going to 175/80 R13. Currently my tires are failing one last year and one this year - tires where new last year. Hoping larger radial tires will be more durable, cannot go larger than 13 or tires will rub on the frame. Are trailer rims lug centering? The larger rim has a larger pilot hole, my current 12 rims have a 2.8pilot hole, will this be an issue?

asked by: Mark

Expert Reply:

According to our resident tire expert, trailer tires often fail because they are not used and maintained as much as automotive tires and/or they are not filled to the recommended psi which would cause a blowout. So it could be that type of issue, rather than the tires being too small. In this case, a load range D tire, 5.3 x 12, like # AM10068, is rated at 1,250 pounds at 105 psi. So total weight capacity of two would be 2,500 pounds. That is very close to the dry weight of the trailer, boat, and motor that you have specified.

Even at a larger size, like 175/80-13, I still recommend a load range D tire, like # AM10210, which is capable of 1,610 pounds at 65 psi. The tire and wheel combination, # AM31985, that you have referenced has this same capacity.

Trailer wheels can be hub piloted, but it is more than likely that your wheels are stud piloted. If your trailer has bolts that screw into the hub, then it is hub piloted and the pilot size will need to be the same. But if you have lug nuts that hold the wheel on, it is stud piloted and a larger pilot diameter is fine.

With the larger size, the tire will be two inches taller and 1-1/2 inches wider. You will need to make sure there is enough space for the new mount and that the bolt hole pattern is the same (5 on 4-1/2).

expert reply by: Michael H