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.
The diameter of the wheel is given in millimetres (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 behaviour of the wheels, such as acceleration vs. speed, manoeuvrable vs. direction stability. The range of diameter for different wheel type and its relevance can be seen here:
Better acceleration <---- ----> Higher speeds
More control <---- ----> Higher direction stability
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 durometer for different wheel types and its relevance can be seen on this figure:
Better grip <---- ----> Longer wear
Lower bodyweight <---- ----> Higher bodyweight
Shock absorbing <---- ----> Higher speeds
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 harder Durometer B scale, B is very near to Plastic/Nylon.
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.
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.
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:
Aggressive Hockey Fitness Speed
Flat profile Rounded profile Narrow profile
More control <---- ----> Higher speed
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 polyurethan, 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.
The core of the wheel is the hub. The hub is centred in the wheel and keeps the bearings positioned. The material is usually hard plastic or aluminium, 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).
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.