How To Determine Trailer Axle Weight Capacity And Replacement Hub Components

Updated 03/08/2016 | Published 03/06/2016

Products Featured in This Question

Dexter Trailer Idler Hub Assembly for 6,000-lb Axles - 6 on 5-1/2

(893)

$131.89

4" Carbon Fiber Digital Caliper

(26)

$12.23

Question:

I read your article on determining axle size. You talk about measuring the he axle...this is were I am lost. I took the tire off my trailer but I am unsure what I am measuring. Help!

asked by: Tonya

Expert Reply:

Depending on the age and condition of the trailer, it may have a sticker or plate that has the weight capacity of the trailer listed.

If you aren't able to find a sticker or plate, you can determine the weight capacity of your axle by using a precision tool like part # PTW80157. Here are the typical axle diameters between the hubs based on axle capacity. You will need to measure the axle beam. the tire does not actually have to be removed for that.
- 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

If you cannot determine the weight capacity using the above suggestions the next step would be to measure the wheel bolt pattern on the hub, the size of brakes, and the bearing part numbers. I have attached a drawing that shows where you can find the numbers on the hub components or where to measure on the spindle to find the right parts. With this information we could narrow it down to what size axle you have on your trailer.

If you are wanting to replace your axle, you can take a couple measurements as shown in the attached drawing to find the right size axle for your trailer.

You would need:
-Hub face to hub face measurement (see diagram)
-Spring center to spring center dimension (see diagram)
-Inner and outer wheel bearing reference number
-Axle capacity