How to ID Your Trailer Axle

If you need to replace a trailer axle, the first step is identifying the exact axle on your trailer. The easiest way to do this is by locating the axle label on the center of the axle tube and reading the axle description number, which contains specifications like hub face, track width, spring center, and brake configuration.

Understanding the elements of your trailer axle description number is helpful for ordering an axle that will perfectly match your RV or trailer suspension. In this post, we’ll break down where to find your trailer axle label and how to identify Lippert-manufactured spring axles.

1. Locate the axle label on the center of the axle tube.

2. Record the axle description number and serial number.

3. Identify key specifications such as hub face and spring center measurements.

4. Confirm whether the axle uses leaf springs or torsion suspension.

5. Use these details to find a compatible replacement axle.

The trailer axle label is typically located on the center of the axle tube on the back side of the beam, underneath the trailer frame between the wheels. This label contains the axle description number, serial number, and manufacturing details needed to identify the correct axle specifications.

To identify a trailer axle, read the axle description number printed on the axle label. This series of letters and numbers contains specifications such as the axle model, hub face measurement, track width, spring center distance, brake configuration, and lubrication type.

On the axle label, you’ll see a series of letters and numbers known as the axle description. This string may seem complicated at first glance, but it actually encodes specific details about the axle on your unit — similar to how a vehicle identification number, or VIN, encodes details about your car or truck.

If your axle does not have a label or was not made by Lippert, our “How to Select the Right Axle” post will help you find the right trailer axle for your needs.

Let’s go over the axle description, so you can find the right replacement axle for your RV or trailer.

Using the example from the image above, you will see that there are 10 to 12 different parts of an axle description. The ABS designation and axle tube part number are not always present.

The first number in the series is the Lippert model designation. Next, you’ll find the hub face and track dimensions followed by the spring center dimension and designations for the tie plate, spring mounting, lubrication and hub or drum.

After the hub or drum designation number, you may see the letters “ABS.” This code will only be present if your unit suspension contains an anti-lock brake system.

Next, you’ll see the leaf spring designation and lead wire length. Following the lead wire length is a number which may not be present in all axle descriptions. If your axle tube is non-standard, then its part number will be listed here.

The trailer axle serial number is stamped or printed on the axle label located on the back center of the axle beam. This serial number allows manufacturers or service technicians to confirm the axle’s manufacturing date, specifications, and compatibility with replacement parts.

To order a replacement trailer axle, you need the axle description number or measurements from your existing axle, including hub face length, spring center distance, and weight capacity. Matching these specifications ensures the new axle fits your trailer suspension and frame correctly.

At Lippert, we build a full line of reliable 2-12K spring axles to meet unique specifications for a wide range of utility trailers, including open and closed cargo, teardrop and travel trailers. Our dependable 2-7K torsion axles are ideal for cargo, marine, agricultural, equestrian and purpose-built trailers.