Trailer Axle Weight Capacity Based on Diameter of Axle Tube

Published 01/09/2018

Question:

Im trying to determine the capacity of the axle on my travel trailer. The campers tag says 3,500, but the previous owner told me he had it customized with a 4,500 pound axle. I found a sticker on the axle, but its in pretty bad shape, and I dont see a weight rating on it. I measured the circumference at 10 inches, which converts to 3.1831 inch diameter. Based on your site's question/answer, thats a 6,000-lb - 7,200-lb axle. Could that be right? The sticker on the axle has a partial serial number, an S/O number, PO number, and says customer is Columbia Northwest. Let me know if a picture of the sticker would help. Thanks

asked by: Todd B

Expert Reply:

The diameter of the axle will only give you a general idea of the capacity. Your reference to our customer question and answer page is to give the general industry sizes. Since you know the previous owner customized it with a 4,500 lb axle, that is the information I would go on. Remember that axle capacity doesn't mean trailer capacity. You may be limited by tires, hubs, leaf springs, frame, coupler, or other components to a lesser trailer capacity.

Another way to narrow down axle capacity is based on spindle measurements. I've attached an article to assist with determining spindle sizes for hub assembly capacity.

expert reply by: Jason S