How to Determine Weight Capacity of Trailer Axle by Measuring Diameter

Question:

i was wondering how you know how much weight a trailer axle can haul or trailer when you are building it yourself. i have a old travel trailer that has been stripped down and it did have trailer breaks on it at one time but i need to know if those axles and frame would be able to handle the weight of a vehicle as i would like to make it into a car hauler. any advise besides going and buying one would be appreciated.

asked by: Deryl H

Expert Reply:

A good indicator is the diameter of the axles if they are round.

Typical Axle Diameters Based on Axle Capacity
- 1,000-lb - 2,000-lb Axles: 1-1/2 inch - 1-3/4 inch diameter
- 3,500-lb Axles: 2-3/8 inch diameter
- 6,000-lb - 7,200-lb Axles: 3 inch diameter
- 8,000-lb Axles: 3-1/2 inch diameter
- 9,000-lb Axles: 4 inch diameter
- 10,000-lb Or more axles: 5 inch diameter

Those suggestions would be the easiest way to find the weight capacity on your trailer axle. If you cannot determine the weight capacity using the above suggestions the next step would be to measure bolt pattern on the hub, size of brakes, and bearing part numbers. With this information we could narrow it down to what size axle you have on your trailer.

expert reply by: Jameson C