This blog provides a comprehensive guide on how to measure casters, detailing the importance of accurate measurements for optimal functionality. It also covers the process of choosing the right caster size for the load and conditions.

Our goal is to help military engineers acquire precise measurements to guarantee optimal caster fit, functionality, and performance in high-stakes military applications. In fact, Aerol casters are used in many commercial and military applications and meet MIL-C-4751, MS24373, MS27281, MS27149, MS24374, and MIL-C-7474 specifications. 

To start, let’s look at how to measure the main parts of the caster, including the top plate, bolt-hole pattern, wheel diameter and width, swivel lead, and overall height.

How to measure the main parts of a caster.


Top Plate—Top plates hold the caster to the object it is moving. These plates are available in various sizes, so ensuring you have the correct measurement is crucial when replacing your caster.
To Measure: Measure both the length and width of the top plate.

Bolt Hole Pattern/Spacing — It’s extremely difficult to change the bolt-hole pattern on the object that the caster attaches to, so you want to make sure you get an accurate measurement so the patterns line up properly. Measure from the center of one hole to the center of the other hole lengthwise. Repeat this process again on the perpendicular side (widthwise).

Wheel Diameter and Wheel Width — For caster wheel measurements, first measure the wheel diameter. Try to get that as centered as possible on your wheel and get the overall diameter of the wheel. From there, you’re going to want to measure the width of the wheel, so use your calipers measure the width of the wheel.

Swivel Lead—The swivel lead is the distance from the center of your swivel section to the center of the axle. It’s also known as the offset and represents how far ahead the wheel is relative to the swivel assembly. You want to measure this to determine the wheel’s offset. Longer swivel leads increase the swivel radius and make turning carts easier, but they reduce the ability to make 90-degree turns

Overall Height of the Wheel and Top Plate — This is the measurement for the overall height of the entire caster assembly. You want to measure from the bottom of the wheel to the top of the top plate. Measuring the overall height can be done with the caster standing up, lying down sideways, or flipped upside down so it sits on the top plate (shown here). Measure from the top plate to the bottom of the wheel.

Additional Caster Considerations

Jacking CasterNow that we have reviewed how to measure a caster, another main consideration is determining your load rating. Industry best practices take the maximum load to be moved and then dividing it by the number of casters minus one. The thinking behind this is that three wheels make a plane, and there will be times when only three of the four wheels will be handling the total load.

For a four-wheel material handling cart, the caster capacity required would be calculated as Caster Load = Maximum Load Being Moved, Three Casters (N-1).

Manual or motorized?

Whether the material load will be manually pushed or moved by towing or by a motorized caster helps pinpoint what wheel materials you will use. Powered and towed carts are generally driven at higher speeds and over greater distances. These towing speeds require special wheel materials for optimal life.

Are there any environmental concerns that need to be addressed? Military components are often subjected to extreme conditions, including high temperatures, heavy loads, and chemical exposure. Aerol’s aluminum casters are designed to withstand these conditions and provide long-lasting performance, reducing the need for frequent replacement and repair.

This makes them a perfect choice for Navy and Coast Guard applications where corrosion is a problem for steel and iron. Another Aerol advantage is the precise handling and positioning during transportation our casters offer, with features like swivel locks and brakes to improve safety and efficiency.

Solutions for Mission-Critical Situations.

Aerol has enjoyed a strong relationship with the military, aerospace, and commercial industries. Our decades of experience in the material handling field led to many innovations that help our customers move both delicate and demanding equipment safely and efficiently. For more information on the range of Aerol Casters and their role in military operations and other industries, contact us. Or, talk to our Aerol solutions specialist:

Alex Harden, BSME

Technical Product Manager, Aerol