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

We aim to help military engineers acquire precise measurements to guarantee optimal caster fit, functionality, and performance in high-stakes military applications. 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 moving object. 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 the caster attaches to, so you want to ensure you get an accurate measurement so the patterns line up properly. Measure lengthwise from the center of one hole to the center of the other hole. Repeat this process again on the perpendicular side (widthwise).

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

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 to 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 measures 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. The caster can be measured 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 divide 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 handle 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 a motorized caster helps pinpoint the wheel materials you will use. Powered and towed carts are generally driven at higher speeds and greater distances. These towing speeds require special wheel materials for optimal life.

Are there any environmental concerns that need to be addressed? Military components often face extreme conditions, including high temperatures, heavy loads, and chemical exposure. Aerol’s aluminum casters are designed to withstand these conditions. These are providing 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 have 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