How to ID Your Trailer Axle

Understanding the elements of your 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.

An axle label can be located at the center of the axle tube, which is found underneath your unit’s frame and between the tires, brakes and springs of your trailer’s wheelbase.

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.

If you need to find your trailer axle serial number, it will always be located on the back of the axle on the center of the beam. Knowing the manufacture date and serial number of your axle is critical for troubleshooting issues.

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.