Ways to Determine Axle Capacity of Trailer

Updated 04/03/2019 | Published 04/02/2019

Question:

only one axel has brakes. how can i tell if it is a 3,500 lb axel? My boat weighs 3,800.

asked by: Phil H

Expert Reply:

There's a few ways to determine trailer axle capacity. You can check the axle for a label which will have it's capacity and length listed, it might be listed on the plate of the coupler that also has the VIN, or you can measure the diameter of the axle. If the axle diameter is 2-3/8 inches then that would indicate you have a 3,500 lb axle. If the drums of your hubs are 10 inch in diameter and 2-1/4 inches deep that would also indicate this too and would mean that the brake assembly set # 40716-15 would fit.

Here's a list of typical axle capacities based on diameter:

- 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

expert reply by: Jameson C