Each skateboard wheel is mounted on its axle via two bearings. With few exceptions, the bearings are the industrial standard "608" size, with a bore of 8 mm (or 10mm depending on the axle), an outer diameter of 22 mm, and a width of 7 mm. These are usually made of steel, though silicon nitride, a high-tech ceramic, is sometimes used. Many skateboard bearings are graded according to the ABEC scale. The scale starts with ABEC1 as the lowest, followed by 3, 5, 7, and 9. It is a common misconception that the higher ABECs are better for skateboarding, as the ABEC rating only measures tolerances, which do not necessarily apply to skateboards. Bearing performance is determined by how well maintained the bearings are. Maintenance on bearings includes periodically cleaning and lubricating them . Bearings that are kept unmaintained have their performance greatly lowered and will soon need to be replaced. Bearing cleaning kits are commonly available on the market. The ABEC rating does not determine the speed or durability of a skateboard bearing. In particular, the ABEC rating says nothing about how well a bearing handles axial (side-to-side) loads, which are severe in most skateboard applications. Many companies do not show the ABEC rating, such as Bones Bearings, which makes bearings specifically for skateboarding, often marketed as "Skate Rated". Each bearing usually contains 7 steel or ceramic bearing balls, although other configurations are used as well.
Skateboards are for people who want to try something new and extreme. If you have not given it a shot and you want to challenge yourself then you should try skateboarding. It is a fact that there are certain risks that go along with skateboarding. However, skateboarding can teach you to balance and it is also a great way of losing weight. Skateboarding can also help you in making friends while you are in the park. With skateboarding, you can learn perseverance and build confidence.
The longboard, a common variant of the skateboard, is used for higher speed and rough surface boarding, and they are much more expensive. "Old school" boards (those made in the 1970s–80s or modern boards that mimic their shape) are generally wider and often have only one kicktail. Variants of the 1970s often have little or no concavity, whereas 1980s models have deeper concavities and steeper kicktails.