How to Measure a Trailer Axle

When it comes to trailers, the axle is a crucial component that ensures stability and supports the weight of the load. Whether you’re replacing an old axle or building a new trailer, knowing how to measure the axle correctly is essential. In this guide, we will walk you through the step-by-step process of measuring a trailer axle.

Step 1: Determine the Axle Type

Before measuring the axle, you need to determine the type of axle you have or need. There are three common types:

• Leaf Spring Axle: This type of axle is typically found on utility trailers and has leaf springs mounted above or below it.
• Torsion Axle: Torsion axles have rubber cords inside the axle tube that provide suspension and dampening. They are commonly used on boat trailers and enclosed trailers.
• Straight Axle: Straight axles are solid and do not have any suspension components. They are often used on heavy-duty trailers.

Identifying the axle type will help you determine the appropriate measurements needed.

Step 2: Measure the Axle Length

The axle length is measured from the center of one hub face to the center of the opposite hub face. To measure the length accurately, follow these steps:

1. Place the trailer on a level surface and ensure it is stable.
2. Measure from the center of one hub face to the center of the opposite hub face using a tape measure.
3. Record the measurement in inches or millimeters.

It’s important to note that the axle length should not include any additional components such as hubs or brakes.

Step 3: Measure the Axle Diameter

The axle diameter refers to the thickness of the axle tube. To measure the diameter, you will need a caliper or a tape measure:

1. Ensure the axle is clean and free from any dirt or debris.
2. If using a caliper, place the jaws around the axle tube and record the measurement in inches or millimeters.
3. If using a tape measure, wrap it around the axle tube and record the circumference. Then, divide the circumference by π (pi) to calculate the diameter.

Make sure to measure the diameter at the thickest part of the axle tube.

Step 4: Measure the Axle Capacity

The axle capacity refers to the maximum weight the axle can support. It is an important consideration when selecting or replacing an axle. To determine the axle capacity:

1. Locate the axle tag or sticker, usually found on the axle beam.
2. Read the information on the tag, which should include the axle capacity in pounds or kilograms.
3. If the tag is missing or unreadable, you can contact the trailer manufacturer or a professional to help you determine the axle capacity based on the axle type and measurements.

Step 5: Verify Other Specifications

Depending on your trailer’s specific requirements, you may need to verify additional specifications such as the axle hub face-to-face measurement, the hub bolt pattern, and the axle camber or bend. These measurements ensure compatibility with your trailer’s wheels and suspension system.

If you are unsure about these specifications, it is recommended to consult the trailer manufacturer or a professional to ensure you get the correct axle for your trailer.

By following these steps, you can accurately measure a trailer axle and ensure you select the right replacement or build a trailer that meets your specific needs. Remember to always prioritize safety and consult experts if you have any doubts or questions.