Skateboarding can be never achieved without wheels. Next to the deck and truck, wheels serve as another major component of electric skateboard. When you’re shopping for wheels at your skate shop or online, are you always getting overwhelmed? There are all these colors and different sizes, and you may have no idea to make a choice. Well, it indeed gets confusing, especially for a skateboard beginner. If you decide to devote yourself into the skateboard sport, spend some time to learn general information about the components of the skateboard. Don’t know where to start? Don’t worry, we’re here to help you know more parameters about wheels.
Material
Most wheels are made of polyurethane, a synthetic hard rubber that improves the performance of the wheel by changing the chemical composition. And people usually refer to it as urethane. This versatile material can be manufactured in varying degrees of hardness. It is a super strong and durable plastic that lends itself perfectly to skateboarding. Polyurethane skateboard wheels can withstand scratching and harsh environmental conditions owing to their enhanced physical properties. Therefore, the urethane material dominates the skateboard wheel market. But not all wheel materials are exactly the same. Different skateboard wheel brands have their own manufacturing formula and raw materials of various quality, and they may combine several materials to make wheels more durable, faster and smoother. So it’s normal that you may feel different when you use wheels with the same hardness that from two different brands. The ideal wheel must be both elastic and hard, fast and durable.
Diameter
Diameter is the first information that you will get about any kinds of wheel that you encounter. Wheel size is important. It can affect your skating in many different ways. The weight, the speed and the style of your skateboarding all depend on wheel size. The diameter of the wheel is measured in millimeters (mm). You need to choose the size according to the spots that you skate. The diameter of wheels differs from each skateboard brand. Normally, the wheels of electric skateboards have a diameter of more than 85mm. For off-road electric skateboards, wheel diameter may even reach 125mm. Wheels with smaller diameter start up and accelerate quickly, but have less drag, making them ideal for flat roads. Wheels with larger diameter start up and accelerate slowly, but with more inertia and impact, making them easily roll over rough ground.
It’s also very important that the diameter of the wheels is adapted to the height of your trucks. If your setup is poorly balanced, you risk the wheel bites, which means that a wheel comes into contact with the board in turns which leads to a sudden stop. Another thing that is going to be impacted by the diameter of your wheels is small rocks or some cracks in the street. On bigger wheels, those cracks and rocks will somehow a bit smaller than what they would have been if your wheels were a lot smaller. Therefore you don’t care so much about cracks and small rocks with a bigger diameter. Smaller wheels are a lot more responsive and lighter and this makes it a lot easier to flip your board. Bigger wheels cover more ground and go faster, and they are not as responsive.
Durometer
Durometer (also referred to as hardness) of the wheels is indicated on a scale from 75A to 101A. The higher the number, the harder the wheel. For instance, a 100A wheel will be harder than a 95A wheel. Hardness can also be described on a B scale. A wheel of 80B is as hard as a wheel of 100A. 101A is the hardest grade in a wheel. Most wheels have only one hardness, but some wheels have double hardness. Generally, the inner layer of a wheel is made of a harder material while the outer layer is made of a softer material. The rougher the contact surface, the lower the hardness of the selected wheel and the lower the sliding sound. Wheels that are too soft are less resistant to abrasion because they are soft, and it is easy to break the spacer layer when doing tricks or braking. Wheels that are too hard have weak grip, making them suitable for very smooth surfaces but prone to bursting.
Generally, the hardness selection goes like:
87A – very rough ground (downhill sliding)
95A – rough ground (streets)
99A – smooth ground (various street markets, skate parks, U pools, swimming pools)
101A – Not suitable for rough or very smooth ground (poor grip due to hardness)
Hard wheels can slide easier, but when you’re sliding it’s harder to control. Another thing is that technically very hard wheels should roll a lot faster than soft wheels. However, in reality harder wheels are very sensitive to the quality of the ground. Therefore, if you’re going on into street missions, you don’t really know how the ground is and it could be crusty, then you want to use softer wheels. The last thing about hard wheels is that for the same shape and size, it would last longer. Softer wheels will tolerate grounds which quality would be a lot lower like with a lot of cracks and small rocks. You will be a lot more comfortable on a board that have softer wheels, but it will be a lot harder to make this board slide on the ground. While for the sliding part, softer wheels will be easier to control. In short, a wheel harder than 89A is perfect for street riding, all other softer wheels are ideal for cruising and filming since they are virtually noise-free.
Core
Nowadays there are two kinds of wheels, that is standard wheels (also called non-core wheels) and core wheels. Core wheels will have a plastic core which is harder than the rest of the wheel. This plastic core saves on weight and also helps the bearings stay in place, keeping them from being forced into the wheel. The cores are used to help dissipate heat caused by friction coming off bearings at high speeds. A core will let you go fast on smooth roads, but has the opposite effect on rougher surfaces. The position of the core can affect the ride of the wheel as well. A side set wheel has the core on one edge of the wheel while the core is in the middle in a center set wheel. Adding a larger diameter core will make a wheel roll faster, which is a great benefit for freeride, and downhill. Wider cores help support the urethane better and promotes even wear. Using a harder material in a core will also improve roll speed and help prevent deformation of the urethane during slides to promote even wear.
Resilience
The resilience of wheels is very important. Although there are no standard parameters to refer to. But the stronger the resilience of the wheels, the greater the ability to cross obstacles. On a smooth surface, both wheels may be able to run equally fast, but the advantage of wheels with high resilience can be reflected immediately when it comes to slightly rough road conditions. If you don't know how your wheels resilience performance, you can do a little experiment. Remove the bearings from the wheels, throw the wheels to the ground to see if the wheels can bounce high.
Contact patch
Contact patch refers to the part of the wheel that stays in contact with the ground. The greater the contact patch is, the more weight will be spread over larger area. This will reduce the urethane compression and the rolling resistance, which means the wheels are more likely to be slowed down. The edges of the wheels are rounded to reduce the width of contact patch, making wheels easier to turn and faster to slide. The smaller the contact patch is, the easier it is for the wheel to slide sideways. A wheel with a wide contact patch which is close to the width of the wheel itself will lock more tightly while doing tricks.
Replacement frequency
It depends on how often you use the skateboard. Typically, wheels should be replaced within three to four months. If you're a frequent skater on rough floors, or if you're a heavier skater, you need to change the wheels earlier. Generally in the following cases, you have to consider the replacement of the wheels: wheel wearout gets serious; diameter becomes smaller; wheel surface turns uneven; sliding speed obviously slows down; bearings are liable to loosen or make noise.