How to Determine Axle Capacity on a 12 Foot Tandem Axle Utility Trailer

Question:

Trailer weight rating capacity, ballpark? I purchased a large utility trailer from my neighbor 2 years ago. 12foot long, 66inch wide. Tandem axle. Front axle has functioning trailer brakes. Decking is 2x8 pressure treated boards. I dont know axle tube diameter at this time. 5 lug hubs. 2inch ball. The tag info is gone, only Phoenix Trailer Glens Falls NY is left..

asked by: Max

Expert Reply:

With 5 lug hubs the capacity per axle could be any where from 2,000 to 3,500 pounds. It is likely that they are 3,500 pound axles but I would have to know the inner and outer bearing numbers stamped into the metal of the bearings to know for sure. This is going to be the best way to determine the axle capacity.

Diameter of a round axle can help but isn't always definitive:

Typical Axle Diameters Based on Axle Capacity
1,000-lb - 2,000-lb Axles: 1-1/2" - 1-3/4" diameter
3,500-lb Axles: 2-3/8" diameter (Can have a 3-1/2" diameter, but rarely)
6,000-lb - 7,200-lb Axles: 3" diameter
8,000-lb Axles: 3-1/2" diameter
9,000-lb Axles: 4" diameter
10,000-lb Or more axles: 5" diameter

expert reply by: Michael H