Wheel terms explained

Most wheels are made of polyurethane. All inline wheels have a standard width of 24 mm, making it easy to change your wheels.

The characteristics of wheels are the diameter, durometer, rebound, grip, profile, wear, hub and weight. A detailed description of all these terms can be found in this guide.

Diameter

The diameter of the wheel is given in millimeters (mm). Usually, this number can be read directly from the wheel or it can easily be measured.
The diameter of the wheel has relevance for the behavior of the wheels, such as acceleration vs. speed, maneuverable vs. direction stability. The range of diameter for different wheel type and its relevance can be seen here:

• Better acceleration vs. higher speeds
• More control vs. higher direction stability

Durometer

This term is the relative hardness of the wheel and is described by an A-number. 100A is very hard, and 0A is soft.

The durometer of the wheel has relevance for how well shocks are absorbed and for the grip. But also wear and speed depends on the durometer. The range of durometers for different wheel types and its relevance can be seen on this figure:

• Better grip vs. longer wear
• Lower body weight vs. higher body weight
• Shock absorbing vs. higher speeds

Durometer alternatives

There are other ways to measure the wheel hardness, some brands use their own scale. I.e Matter wheels from the USA uses the Footprint scale, the F0 stands for footprint 0.

• F0 - equals approx. 88A
• F1 - equals approx. 85A
• F2 - equals approx. 84A
• F3 - equals approx. 83A

Durometer A is softer than the Durometer B scale, B is very near to Plastic/Nylon.

Rebound

One of the important factors for how fast you can roll. The rebound is a term for how much force you will be pushed forward with each stroke (the response of the wheels). Sadly the rebound factor is never given for wheels, it also depends very much on the material of the wheel. A high rebound is usually one of the characteristics of expensive quality wheels. Lots of manufacturers call their high rebound wheels SHR urethane. Super High Rebound.

Grip

The grip is very important for speed and hockey, where a good grip allows you to stop quickly and turn fast corners. The grip depends on the material of the wheel and its durometer. But also the type of surface (asphalt, track, indoor, wet conditions) is very important, and the best skaters often bring wheels with different grip to different surfaces.

Profile

The cross-section of the wheel is named the profile. A narrow profile results in little road contact and higher speed, but a wide profile results in more road contact and more control. See the typical profiles for different wheel types:

1. Aggressive, flat profile, small diameters, very high control
2. Hockey, rounded profile, high control
3. Fitness, narrow profile, all-rounder
4. Speed, narrow profile, large diameters, high speed orientation

Wear

The wear of the wheels naturally depends on the durometer and diameter of the wheel, but it depends even more on the quality of the polyurethane, the rubber on the wheel. For hockey use, it is important to get a good quality, if not you risk to wear out your wheels in a few hours.

Hub

The core of the wheel is the hub. The hub is centered in the wheel and keeps the bearings positioned. The material is usually hard plastic or aluminum, and for the best performance, it needs to be strong and light. There are different hubs, which differentiate in stability and weight.

Solid core wheels have a massive core and are therefore very strong. Spoked core wheels are a lot lighter, but not as durable as solid core wheels. Hollow-core wheels are a compromise between lightweight and durability (not as strong as solid core).

Weight

The weight of the wheel is also important for how fast you can go. Lower weight means you need less force to make the wheels rotate.