How to Determine the Capacity of a Trailer Axle

Published 10/27/2014

Question:

How do I find our the axle weight capacity? Is it marked on the axle somewhere?

asked by: Todd

Expert Reply:

The axle could have its capacity information on a tag on it or stamped into the metal. There may also be a plate on the trailer frame somewhere listing the axle capacity.

I could give you a good estimate if I knew the diameter of the axle (if it is a round axle) and/or by the inner and outer bearing numbers stamped into the metal of the bearings.

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