Bearings are mechanical arrangements fitted inside the wheels. They are kind of intermediates between a wheel and an axle. They reduce friction, thus increasing the wheel’s rate of rotation.
There are two situations a skateboarder can be selecting the bearings: when assembling a new skateboard from pieces or when the old bearings went out of order.
Choosing bearings is quite simple. It’s hard to fail since all the skateboarding bearings are standardized: one size fits any wheel. Still, there are some details to be aware of when choosing your skateboard bearings.
This post has been written for those who want to scrutinize the structure of bearings, learn what materials they are made of, and what the mystic ABEC acronym followed by a number means.
Components of a Bearing
Bearings, officially known as roller bearings, conical roller bearings, and a roller bearing assembly, are relatively simple mechanical arrangements. They consist of two rings, rolling elements (balls), a ball retainer, and bearing shields.
A skateboard bearing typically includes 6 or 7 balls that roll one after another along a groove between the outer and inner rings.
Outer and Inner Rings
Outer and inner rings form a ‘track’ that the balls follow. The outer ring remains immobile relative to the axle, while the inner ring rotates as the balls roll.
A ball retainer is a special ‘carrier’ containing the balls located equally apart. The purpose of the ball retainer is to reduce friction and increase robustness.
Bearing shields are intended for protecting the interiors of the bearing from dust and mud. Some bearings are maintainable, which means their bearing shields can be split open. Others have the shields fixedly attached, meaning they can not be mounted back once removed. In some cases, there is only one bearing shield from one side of the bearing merely to reduce the friction.
Some bearing sets are complete with tailored bushings. Those are small cylinders placed between bearings inside a wheel. Bushings are designed to align bearings for maximum friction reduction and hence speed increase.
What Is ABEC
When choosing bearings in a skateboard shop, you’ll notice several kinds of bearings with various numbers following the ABEC notation, like ABEC-3, ABEC-5, -7, or -9 rating.
The ABEC acronym stands for American Bearing Engineering Committee, a division of Americal Bearing Manufacturers Association engaged in bearings development. This acronym is also a standard for precision bearding manufacturing. The higher the number, the more precise the bearings: ABEC-1 are regular bearings, ABEC 3 are extended precision bearings, ABEC 5 are high precision bearings, ABEC 7 — precision bearings, and ABEC 9 are super-precision bearings.
Many people think the higher the number, the better the bearings since they are more expensive. There is also a belief spread among skateboarders that increased rating of the bearing also increases the speed of the wheels. This belief is correct in general, but not in terms of skateboarding. For example, 7- or 9-rating bearings can develop rotation speed up to 20-30 thousand revolutions per minute. With a 54mm diameter wheel, this would be equivalent to the speed of 200 kilometers per hour (about 124 miles per hour).
The ABEC rating leaves out such aspects as impact/shock resistance, lateral distortion resistance, materials, lubricant, noise emission, and vibration. In skateboarding, though, these aspects are much more important than manufacturing precision. That is why this rating is not so essential when choosing your skateboard bearings.
So, we recommend you forget about the ABEC rating and remember this: the fastest bearings are the ones regularly maintained and lubricated.
Material for Skateboard Bearings
Steel bearings are a skateboarding standard. They are both reliable and budget-friendly. Steel bearings are grouped into those made of chrome-plated steel and stainless steel.
The disadvantage of chrome-plated steel is that such bearings are corrodible in the event of moisture ingress. So, if you are using chrome steel bearings, they need to be regularly maintained and relubricated. You should also avoid skateboarding in the rain or over puddles. But if your wheels did happen to get wet, they should be cleaned and relubricated once you’ve dried them up.
Stainless steel bearings are not corrodible, so they are not afraid of puddles and rain. Well, until the time is ripe. If you keep skateboarding in the rain, the lubricant used to reduce friction will be gradually washed out from the bearings, leaving there just mud, contributing to a faster wear out. So, stainless steel bearings also need to be serviced once in a while.
Ceramic bearings are much harder than steel ones. Also, ceramics is much more thermoresistant, whereas the less expansion of bearings material is due to heat, the faster the speed. Another advantage is that ceramics is not susceptive to corrosion.
There are three types of ceramic bearings:
- Only one ball out of seven is made of ceramics. Technically, this ceramic ball is supposed to clean the groove from dust, but this doesn’t exactly work this way in reality. Fundamentally, such bearings are not much different from usual steel ones, except for the price.
- All the balls are made of ceramics; the rings are manufactured of steel. This is the most reasonable option. The balls wipe out the groves and do not corrode. There is a disadvantage, however: because ceramics is harder than steel, the balls may distort steel rings with a strong load, which will adversely affect the speed.
- Balls and rings are all made of ceramics. This is the most expensive and very rare option which is not practically reasonable. Such a bearing will certainly not rust, but do you really need a set of bearings at a price of a skateboard? Besides, such bearings may simply break down in the event of a very strong load. So, if you plan on jumping from the stairs, this is definitely not your option.
Titanium is a light, reliable, and corrosion-resistance material. Titanium bearings are similar to steel ones, but they are supposed to work longer and corrode less. Well, in theory.
In reality, there are no titanium bearings. Titanium is costly and hard to process. When manufacturers declare their bearings are manufactured of titanium, they mean that steel or ceramic balls are coated with titanium dust. And you should know, this dust coating won’t stay long on the bearing balls and will eventually wipe away. So, don’t let yourself be fooled by the ‘titanium’ labeling!
If it’s your first time buying bearings and you don’t want to bother, simply choose an inexpensive set of steel bearings, and that would be it. But if you are not happy with this option because you want speed and reliability, and you don’t plan on jumping from up high, it makes sense considering ceramics bearings.
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