Thanks to Albert Ferdinand Shore, there is a device that can  measure the hardness level of polymers and other forms of plastic and rubber. He called the device a “durometer,” and referred to the measurement as “durometer,” as well. While there are a variety of hardness testers that came about, he coined the term “Shore hardness” in the 1920s. By measuring the hardness or softness of a caster wheel material using durometer, we can determine which materials are best for certain caster and wheel applications.

About Durometer Scales and Measurements

There are varying scales of durometer used for different plastic materials, commonly A for soft plastics and D for hard plastics. The actual measuring tool, or durometer, is generally a small hand-held gadget with a readout and a handle. A durometer measures indentation depth of a material, which is based on force applied to a presser foot. Several factors are involved in terms of depth: material hardness, viscoelastic properties, presser-foot shape, and test duration. By determining the durometer and scale of a wheel tread material (such as rubber, phenolic resin or polyurethane), one can determine how a particular wheel will perform in the environment where it will be used and thereby select the appropriate caster and wheel products for the application.

Varying Durometers and Readings

By having access to varying types of caster wheel durometers, ordering caster and wheel sets just got easier. The different types of durometers can help measure wheel hardness based on the environmental where they will be used: push or pull applications, other types of applications, type of flooring involved, certain specifications required, and more. The following graphic is a brief example of how tread materials measure in terms of durometer readings and the hardness scale.

The Bottom Line

The harder the wheels you select, the easier it will be to push or pull loads. The softer the wheel you select, the better protected the floor will remain. CasterDepot offers a full selection of caster and wheel solutions, so let us be the durometer guide for your next caster and wheel order of any size.