How to Determine Axle Capacity When Tag is Missing

Updated 06/06/2018 | Published 06/04/2018

Question:

I have a homemade trailer I bought cant find any info on the tag or axle as for as weight limit. Its a 6x12 foot trailer. I know the axle is bigger than 2 inches in diameter just by looking at. But how do i measure the diameter of the axle while its under the trailer? What tool should i use

asked by: Kelly R

Expert Reply:

If you cannot locate any type of information on the trailer itself, either on the axle or somewhere on the frame, then measuring the axle diameter can usually give you a good idea as to its capacity. When measuring the axle, you will want to measure along the actual axle tube - anywhere between the spring seats will work fine. I recommend using a digital caliper like # PTW80157 so you can be sure the measurement is accurate.

The typical axle capacities based on their diameters are as follows:

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 (most likely what you have)
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: Chris R