How to Measure Trailer Axles

Oct 23, 2018

Last Updated on June 28, 2024 by Scott Miller

Last Updated on June 28, 2024 by allprotrailersuperstore

How to Measure Trailer Axles

When you need to select a new trailer axle, measuring it properly so you can either give the salesperson the correct dimensions over the phone or order it correctly online is essential.

Table of Contents

There are three axle types.

  • Straight axles: These types of axles are nothing more than a straight square or round bar.
  • Drop axles: Drop axles possess offset spindles and drop slightly lower than a straight axle.
  • Torsion axles: Torsion axles resemble a rectangular or a square straight axle, but their bars contain moving parts.

When you select an axle, you need to determine its capacity required for your trailer, based on all the components of your trailer and their lowest capacities. In other words, you’re looking for the chain’s weakest link. These components include:

  • Frame
  • Axle
  • Spindles
  • Bearings
  • Hubs
  • Tires
  • Wheels
  • Springs
  • All the necessary hardware to keep the above components in place

Measuring Trailer Axles

When you select an axle, you should keep the following specifications in mind.

  • Load capacity: The axle’s load rating needs to support the maximum gross vehicle weight (GVW) rating. If your trailer has multiple axles, you need to divide the GVW by the number of axles to help you determine each axle’s minimum load capacity.
  • Track length: You determine this by measuring the distance between the center of one tire to the other center, which is also called the axle hub face. You can obtain a more precise measurement by calculating the distance from one hub mounting flange to the other flange, which is the mounting surface. It’s where the wheel studs are.
  • Drop: This measures from a spindle’s centerline to the main axle tube’s bottom. Remember, straight axles have no drop.
  • Spring center: This measurement is crucial. If you don’t get it correct, or do it badly, you may bend the axles. It’s difficult to do alone, so it’s a good idea to get a friend to help. The measurement is between the center of one spring to the center of the other spring. If you can’t find a friend to give you a hand, you can cheat by hooking a tape measure to the outside of one spring and pulling it out the inside of the other spring.
  • Axle spring center pads: These are located at the top or bottom of an axle’s main beam. They are either loose or welded on. It is extremely important not to drill holes in the beam if you’re not going to use spring pads. Drilling will create stress points that will weaken the axle beam, and will also allow water to enter.
  • Total length: Determine this measurement by taking the distance between the two ends of an axle’s spindle.
  • Type of axle: You need to determine what kind of axle you are using — see above for the three main types of axles. It’s vital to decide if you are reusing your current or refurbished mounting hardware, and also helps determine the correct clearance.

Measuring Trailer Axles

Understanding What an Axle Does for Your Trailer

Axles are essential, because without them, there would be no trailers. We don’t see them very often. They are not like the headlights, the windshield wipers or even the tires. You probably don’t even think about them very often. But they are one of the most important components involved when it comes to keeping your trailer on the road. Knowing your axles are reliable means a great deal if you use your trailer to make a living.

While axles are essential parts of any kind of trailer, let’s look at how they work for one particular kind of trailer: the utility trailer.

  • Axles for utility trailers, which include trailers like dump trailers, equipment trailers or landscape trailers, fall into two different types: the straight axle — also called the spring axle — and the torsion axle. They perform the same function, but the way they do it is quite different.
  • Straight or spring axles on trailers usually have the axle slung over the springs, which increases load stability on a lower trailer and makes them easier to load or unload. They are the preferred option for trailer suspension systems, especially for multi-axle trailers, because they are inexpensive and easier to maintain. They usually get manufactured and shipped with pre-attached curve spring plates so they are ready to install, which also helps reduce the cost.
  • Tension utility trailer axles don’t use any metal springs. Instead, several long rubber cords are inside the square tube. They have an inner core piece attached and secured to the tension arms. If you’re transporting your trailer across uneven or bumpy ground as the wheel moves up and down, the inner bar compresses the rubber cords. The corners and edges of the center support become the only contact points. Tension trailer axles are quieter, adjustable for ride height and are more corrosion-resistant because they are totally galvanized. Their major drawback: If you need to make any major repair to them, you are going to have to cut the axle off.

Regardless of their functions, however, you can see why it is so important to measure your axle properly. Whether you need to replace a straight/spring axle that has become worn or corroded over time, or you have a damaged tension utility axle that needs some form of major repair, measuring the axle properly means you will get your utility trailer back on the road quickly, allowing you to resume your work in no time.

Why Measure Trailer Axles?

When you realize you need to order a new axle, you may be able to get the measurements from the axle’s original sticker. In most cases, however, wear and tear will have obscured this information over the years. When ordering a new axle from a professional trailer salesperson, you should let them know the following information.

What an Axle Does for Your Trailer

1. What you are currently using on your trailer

The axle you want to buy should be just the same as the axle you are currently using on your trailer. Again, look above to see the three kinds of axles. Getting the same type will help you avoid problems with clearance. After all, if you’ve been using a straight axle and you order a tension axle by mistake, your clearance factor might not be the same with the loads you haul regularly. Make sure you tell the salesperson if the springs are over or under the axle when you select your part numbers.

2. Track measurement

This measurement is also called the track length. Remember, only measure hub face to hub face to determine this measurement. If you measure from the back of the hub or the brake flange, you will end up with an incorrect measurement.

3. Spring center measurement

As we mentioned above, this is a key measurement, because if you get it wrong, you will end up bending or even breaking your axles. Again, measure from one spring center to its opposite counterpart, which tells you where your springs will connect on the axle.

4. End-to-end spindle measurement

To get this measurement, you need to take the wheels off both sides of your trailer. Then, place your tape measure on the outside of one spindle and pull it to the same point on the opposite spindle. Tell the salesperson taking your order you are giving them a tip-to-tip spindle measurement. If you’re taking this measurement for a boat trailer, you need to subtract five inches for trailers weighing 2,000 to 3,500 pounds. This will give you your hub face measurement.

If you’re not exactly sure how to measure a trailer axle, or if you want to know if you’re doing it the right way, your salesperson will be able to help answer all your questions.

Why Measure Trailer Axles

What to Do If Your Axle Is Broken

If your axle is broken inside your springs, you could be in rough shape. But if it’s broken outside the spring, you can still get the measurements you need to order a new axle if you can still do a spring center measurement, or if the axle remains intact on one side.

In either of these two conditions, you can take the spring center measurement as detailed above. You can then get your hub face length by measuring from the spring center to the outside of the hub face. Double this measurement, then add it to your spring center measurement to get your hub face length.

How Do I Keep My Axle in Good Shape?

All axles wear out over time, but you can keep yours in better shape with a little bit of prevention.

  • When at all possible, avoid hauling your trailer over bad roads. Bumps and potholes do more damage to your axles than you can imagine.
  • Sometimes, it’s impossible to avoid poorly maintained roads and inclement weather conditions. Over the years, a lot of grease and dirt will accumulate on your axles. People will often clean the visible parts of their trailers, but totally forget about the undercarriage. Wash you trailer regularly — if not by hand, take it to a good car wash every month or so, depending on how often you use it.
  • Take a few minutes before you hit the road, especially if you’re taking a long trip, and inspect for rust or cracks, especially where the spindles meet the axle tubes. Wear and tear could be the first sign you are going to need to replace your axle at some point in the near future.

Keep Axle in Good Shape

Why Is It Important to Measure Your Trailer Axles?

If you need to replace the old, worn or broken axle on your trailer, it’s vital to take proper measurements so you can be sure to order the exact replacement you need. If the measurements are incorrect, you’ll end up with the wrong axle for your trailer, which will lead to many other, more expensive problems.

The other benefit to taking measurements ahead of time is that when you call to order your new axle, you’ll be ready with all the information the salesperson needs to assist you. If you haven’t done the measurements, trying to order a new axle based on what you think you know about your trailer and what it needs could result in the wrong axle for the trailer.

Take time to do it properly. As we mentioned above, it might be a good idea to have a friend help you. Even if they’re not helping you take any actual measurements, you can call out these measurements to them, and they can write down the numbers for you.

When you call the Trailer Superstore to order your new axle or place your order online, and if you’re not sure you’ve done your measurements correctly, you can either speak to a salesperson or open a chat window. The person you speak to or chat with will be able to help you determine if you’ve done everything correctly or otherwise help you understand why your measurements may not be correct, and what you need to do to get the proper ones.

Axle From Trailer Superstore

Order Your New Axle From the Trailer Superstore

Family-owned and -operated, Trailer Superstore started by servicing the trailer needs of its customers in the Pennsylvania area. But over the past 30 years, as we have grown, so has our customer base, and we now help many clients around the world.

We carry an extensive line of trailers to satisfy every need, vehicle or budget. Whether you want a new, used or custom trailer, you’ll find what you need here at Trailer Superstore. We also carry many trailer accessories and components. If you need to order a new axle, please contact us, and one of our experienced sales team members will help you.

You can either call us toll-free at 800-622-7003 or visit our online contact page, where you can let us know the details of what you’re looking for and one of our staff will get back in touch with you as soon as possible. No matter where you live in North America, Europe or even South America, the Trailer Superstore will help you find what you need, quickly and at a great price.