Wheels
There are primarily two properties for wheels that are decisive in whether your skateboard works for you: diameter (size) and hardness.
For some reason, the size of the wheels is measured in millimetres, while the boards are measured in inches. Wheels with a larger diameter can reach higher maximum speeds, roll over larger bumps in the ground but accelerate more slowly and have a greater risk of wheelbites, i.e., when the wheel comes into contact with the board on a turn or hard landing, bringing you and your gear to an abrupt stop.
The primary advantage of smaller wheels is that they make the board less clumsy, especially when it comes to flip tricks. Small wheels also provide a lower and more stable centre of gravity for the board, minimising the risk of wheelbites. Your choice of wheel size also depends on whether you have high or low trucks, but we’ll come back to this in more detail in the section on trucks.
Skateboard wheels are made from a kind of superplastic known as polyurethane. The hardness of polyurethane is measured in durometers (designated with the letter “A”), where 101 is the hardest.
Softer wheels roll more quickly over rough surface and do not tend to get stuck as easily on small obstacles on the road, but have more glide on slides and edge tricks.
Hard wheels have lower friction on the ground, and the board feels freer on flip and shove it tricks. Having less grip also implies that you need hard wheels for all types of tricks in which you slide with the board and wheels against all kinds of edges. Hard wheels also roll better on smooth surfaces such as ramps and skateparks, but can be really difficult on rough ground and gravel.
With all these factors in mind, choosing wheels can be quite tricky. Tricks, surface, speed, control, comfort and the risk of wheelbites are all things that need consideration before making your choice. Let’s try to make things simpler. Today, streetboarders tend to choose wheels with a hardness ranging from 98 to 101 A and a size between 50 and 55 millimetres. Ramp and park skaters also choose the same hardness but prefer a size exceeding 60 millimetres. Longboarders prefer larger and softer wheels than streetboarders and ramp skaters, and do not seem to have any upper limits for size and softness.