What’s out of sight gets easily out of mind. It explains why not many people think about trailer axles when checking out parts like tires, headlights, or windshield wipers. Yet, your vehicle wouldn’t go anywhere with trailer axles; it’s important to know how to measure trailer axles if any issue arises. Come with us and find out more.
Main Options
Axles are vital for all types of trailers but are particularly important for utility trailers, like dump trailers, landscape trailers, and equipment trailers. In such cases, there are two kinds of axles: spring axles and straight axles. Both types are necessary for the trailer’s stability while loading and unloading. Multi-axle trailers use them on suspensions since they’re cost-effective and easy to maintain.
Some trailer parts use rubber cords instead of metal springs. This option is suitable for when you’re expecting to drive on bumpy or uneven terrains, as they’re much more flexible. Indeed, tension axles are so flexible that you can easily adjust the trailer height and are naturally more corrosion-resistant.
Knowing How to Measure for New Axles is Crucial
You’ll need to replace your axles occasionally. Sometimes, you can find this information printed on the original axle. Yet, this precious information often wears out over time. That’s when you’ll need to know how to measure them. Otherwise, ordering a new one from an authorized provider will be much more difficult.
Here is some critical information your provider will ask you.
- The type of axle you’re currently using
- Measurements:
- End-to-end spindle measurement
- Spring center measurement
- Track measurement
Typically, drivers always prefer to buy the same type of axle. If you get different axles from the ones you usually do, ground clearance and hauling might be affected. The salesperson will also need to know where the springs are placed.
The track length is the face-to-face length between hubs, ignoring the brake flange and the back of the hub. The spring center measurement points where springs and axles connect. You’ll also need a tape measure to check the end-to-end distance between spindles.
Important Numbers
While shopping for new axles, you must observe if their load rating is enough to handle your GVW (maximum gross vehicle weight) rating. Additionally, ensure you have the exact spring center and drop measurements if you’re not using a straight axle. Otherwise, you’ll risk bending the axle. Don’t forget to check the conditions of the axle spring center pads, which should not be drilled and are typically welded on.
Step-by-Step Guide: How to Measure Axles on a Trailer
If it’s your first time measuring axles and you still don’t know how to do it, don’t worry. Indeed, it’s so easy to do it that you can do it in your garage. You’ll need a tape measure, a level, a caliper, and a notepad to take note of everything. Here’s a straightforward step-by-step guide on how to measure axles on a trailer.
- Preparation: Level your trailer and ensure it’s secured and on an even surface
- Check hub faces: Measure the distance between hub faces using a tape measure.
- Spring Centers: Check the distance between the spring pads’ centers
- Axle Beam Diameters: Use a caliper to measure the axle beam diameter
- Different Bolt Patterns: Observe bolt patterns by noting the distance between them and whether they use lug patterns of five, six, or eight.
Indeed, you can learn a lot about your axle by observing its bolt patterns. Five-lug bolts are commonly found on 3,500 lb axles and prevalent on 4.5-inch patterns. In contrast, the typical 5,200 lb axles have a six-lug 5.5-inch bolt pattern.
It’s possible, albeit more challenging, to measure your axle even if it’s bent or if the hub is missing. You may not achieve the exact measurement, but you can still get a decent approximation of its dimensions. For instance, if your hub face is bent, you can add the spring center measurement to the double overhang measurement to find the hub face length.
Alternatively, you can measure brake flange-to-flange distance if axle hubs are missing. If you have 6,000 lb or 7,000 lb axles, you must add 9 inches of flange length. Likewise, add 6 inches for 3,500 lb axles and 7 inches for 2,000 lb axles.
However, if you can’t measure flange-to-flange distances, finding hub face distance is still possible using overall length. Simply subtract 5 inches from the overall measurement of 2,000 lb and 3,500 lb axles. Subtract 6 inches from the overall length of 6,000 lb and 7,000 axles to find their hub face distances.
Important Tips
Buying new axles isn’t rocket science. Still, you should remember a few things while shopping for a replacement. Here are some tips to guide you in choosing and saving you time.
Read the Specifications
This simple but often overlooked step can save you a lot of trouble. Check your trailer’s manual for specifications regarding the type and number of axles you’ll need and their load capacity. An axle’s load capacity must be enough to handle the ATM ratings. Reading the specifications is usually the easiest way to get accurate information about relevant measurements.
Leaf Springs
If your axles have leaf springs, you must also observe how they work with the frame once installed. Slipper and Eye-Eye are the most common types of leaf springs; while the first is best for heavy-duty vehicles, Eye-eye parts are usually found in lighter-weight options. If there are no leaf springs on the axles, it indicates that you shouldn’t use torsion axles. Leaf springs also vary in length, and longer springs often provide smoother rides.
Mounting Position
The mounting position is where the axle joints the trailer structure. The distance between the leaf springs and the spring center indicates the mounting position. However, if you’re using torsion axles, you’ll have to measure the brackets’ width, since torsion axles don’t require mounting.
Wheel Size and Loaded Deck Height
These are crucial variables you must consider when choosing a new axle. You’ll need your trailer to sustain its height even when loaded. As a rule of thumb, the load capacity of tires and wheels should be superior to those of the axles.
Vehicle’s Type and Size
Your trailer axles should be capable of handling your everyday usage. It means that if you bought a trailer to brave uneven terrains and carry heavy loads, you’ll need similarly sturdy axles. Traveling axle trailers can usually get by with a 4-inch cylinder. However, a 5-inch cylinder can optimize the axle function, delivering 56% more push force. If you want more adaptability and endurance, 4-inch I-beam cross-members on a 4-beam frame might do the trick.
How to Choose the Best Option
Now that you know why axles matter, it’s time to learn how to choose the best one. Your choice will largely depend on your needs. Here are your options and what you can expect from each.
Single and Tandem Axles
Cargo trailer owners typically have to choose between single or tandem axles. Single axles are recommended if you only carry light loads, while tandem axles are more suitable for heavy-duty purposes. Tandem axles also provide superior control on uneven terrains and at high speeds, resulting in a smoother ride. It’s a more expensive option, though, as it demands more from tires and more frequent maintenance as well.
Torsion, Spring, and Drop Axles
When choosing between these suspension systems, remember that torsion axles use a rubberized torsion bar and require little maintenance. They provide a smooth, silent ride but are typically more expensive than spring axles. Spring axles can handle various trailer sizes and payloads but require regular maintenance. They’re a cost-effective option for utility trailers.
Drop axles provide more stability by lowering the trailer’s center of gravity, making the load/unload process much more comfortable. Drop axles can also be combined with other suspension systems, like those mentioned previously.
Load Capacity
You choose axles that can handle your expected cargo demands. Typically, 3,500 lb axles can hold 3,500 pounds (1,587kg) each. Two 3,500 lb axles can handle 7,000 lb load capacity or about 3,000kg. The same principles apply to 5,200 lb axles.
Maintenance and Replacement
Trailer axles should be replaced every 3-5 years, although they can last longer, depending on usage. During this period, they should undergo regular inspection and maintenance to ensure their safety and reliability. Trailer axles are exposed to the elements, and the weather also affects their durability.
Most trailer axles wear out more quickly in icy environments, making them more vulnerable to corrosion and rust. The extreme heat of the Southern regions damages trailer axles, as a dry environment makes them more easily crackable. Likewise, extreme temperature swings like those found on Midwestern roads can also damage your axles, and that’s why they need regular maintenance.
Your maintenance routine will also depend on your trailer type. Axles wear out more quickly on open trailers and last longer on enclosed trailers. Additionally, consider your mileage, as your axles might need maintenance after a few hundred miles.
Signs That Your Axles Need Replacement
You shouldn’t wait until a malfunction on your axles gets you out of the road. When it’s time for a replacement, your trailer axles clearly show one, if not all, of the following signs.
Misalignment
Misaligned axles have a terrible impact on your trailer’s driveability, as it’s much more challenging to maneuver with misaligned wheels. You’ll notice it when the trailer pulls to the right or left while towing. Replace them immediately, as it’s hazardous to drive on misaligned wheels.
Vibrations
If you know your vehicle well, you’ll probably notice when it vibrates differently while driving or towing. Such vibrations are typical signs of damage to your axles, which can ultimately compromise your safety.
Leaks
If you notice grease leaking underneath your trailer, it might be a sign of damage to your axles, like broken or cracked components. Anyway, you must stop driving as soon as you identify the leak. You don’t know what’s causing it, which could lead to catastrophic failures and accidents. The grease that leaks from an axle can also damage other parts of the vehicle, including the chassis, compromising the vehicle’s driveability.
Unusual Noises
Modern vehicles aren’t supposed to be noisy; you should pay attention to rumbles and noises. More importantly, you must pay attention when they occur, such as when hitting a curb or driving on uneven roads.
Safety Measures
Adequate and reliable trailer axles are indispensable for a smooth and safe ride, despite the size and purpose of your vehicle. You’ll need to replace it every 3-5 years, depending on your usage level. That’s why you need to know all about it: how to choose yours, how to take care of it, and when it’s time for replacement.
If you know how to measure your axles, it’ll be easy to replace them, maintain the same performance, and adjust their capacity to new demands. Additionally, you can inspect your vehicle regularly at home, as some problems can be repaired if you identify them early.
Bibliography
- 9 Tips For Selecting The Right Axle For Your Trailer. Tow Max. December, 2021.
- How do I know it’s time to replace my trailer axles? Blue Swift Axles. April, 2023
- Johnson, Aaron. How to Measure a Trailer Axle. Johnson Trailer Parts. May, 2024.
- Miller, Scott. How to Measure Trailer Axles. All Pro Trailer SuperStore. October, 2018.
- Reed, Brandon. Choosing The Right Axle Size And Axle Type For Your Cargo Trailer. Unknown date.
