How To Determine Axle Diameter And Size

Updated 03/23/2018 | Published 03/22/2018

Question:

Seems like the answer is obvious. I'm just second guessing myself. I have a round axle for my boat trailer. If I measure the total length around the axle, it measures 8. Does this mean I have a 4 inch axle?

asked by: Beth B

Expert Reply:

Ideally you can get the measurement of your axle by using a precision instrument like a digital caliper similar to Item # PTW80157. There is also often a sticker or a tag on your trailer axle that tells you the weight capacity of your axle which can also help determine size. Some common axle sizes are:

Round, 1-3/4 inch diameter = 2,000-lb axle
Round, 2-3/8 inch diameter = 3,500-lb or 4,400-lb axle
Round, 3 inch diameter = 5,200-lb to 7,000-lb axle

If you are looking to replace the bearings and seals on your trailer, you can normally find the replacement numbers stamped on your hubs. If you are wanting to replace your hub, I will be happy to help you out if you send me these measurements or part numbers.

If this does not give you what you need, send us more details on what you are wanting to do and pictures and we can make specific recommendations.

I am also attaching a video and some articles that will hopefully assist you.

expert reply by: Brint H