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Skateboard Bearing Dimensions – A Detailed Guide

Fact checked by Michael Derosier

skateboard bearing dimensions

The wheels are the last receivers of a skater’s actions. They respond to pushing, sliding, braking, and other movements on the roads and parks. And like any skateboard part, wheels also differ in size.

But if there is an exception, it’s their bearings. These wheel interiors usually don’t vary in size. If this statement confuses you, it’s time to learn about skateboard bearing dimensions. Here, you’ll see how uniform bearings are from one brand to another.

What Size Are Skateboard Bearings?


Are all bearings the same size? As mentioned, skate bearing dimensions are almost identical. But first, let’s identify the areas measured on this wheel component.

  • Core – The core is the space in the center of the bearing. It’s where the axle pin runs.
  • Outer diameter – This is the measurement of the bearing’s largest part. It extends from one side of the bearing to the other.
  • Width – The width depicts how high the bearing is when seated on a flat surface.


Generally, skateboard bearings come in 608 bearing dimensions with the following figures.

  • Core – 8mm
  • Outer diameter – 22mm
  • Width – 7mm

Are there exceptions? Yes.

608 bearings are the best in the market today, like the famous Bones and Bronson. But we should also acknowledge how 627 wheel cores dominated the sport before, though they’re only in a few skateboards now.

608 and 627 have slight differences in skateboard bearings size.

Don’t worry because it’s not another info memory game. The most significant difference between a 608 and a 627 wheel core is the latter has a 7mm inner diameter or core.

One way to distinguish the two is by looking at their shield stamps. If you notice, some bearings have ZZ or RS suffixes, like 608ZZ or 608RS. Are they different from the numbered shields? No. But what do these indicate?

  • ZZ means your bearings contain shields on both sides.
  • RS describes the kind of shield you have, which is rubber.

Some brands manufacture bearings with shields and their size imprinted on the product. However, other wheel cores may come without these protective layers. And in that case, we’ll seek other methods of identification.

Essentially, 627 wheel cores use 9/32″ hardware, while a 608 with an 8mm core uses 5/16″ nuts.

So, where can we see 627 bearings? Most of these wheel interiors sit on high-end skateboards and classic skateboard models.

What Are Skateboard Bearings Made of?


Besides the size, skateboard parts also vary in material composition. For better discussion, let’s divide a bearing into various components.

  • Outer seal – Usually made of rubber, the outer seal helps protect the bearing from dirt penetration.
  • Ball retainers – Ball retainers commonly come in steel bodies that house the ball runners to maintain equal spacing. They also keep these small parts intact inside the bearing.
  • Ball runners – Ball runners may come in steel or ceramic materials.
  • Casing – The casing consists of two parts: the inner and outer ring. Whether you buy steel or ceramic bearings, these two use steel as the primary material.
  • Bearing shield and C-Ring – These are on the opposite side of the rubber seal. The bearing shield works exactly like the rubber layer on the other side. And the C-ring locks these layers in place.

With all these parts and their material composition, ceramic and steel stand out as common choices. So, how is one better than the other?

Ceramic bearings require less maintenance than steel. They also last longer because they don’t rust quickly. In performance, this bearing type works faster than its steel counterpart.

While steel is a favorite choice for budget-conscious riders, others would still gamble on ceramic because of its overall quality.

ABEC Ratings

The most popular gauge in picking skateboard bearings is the ABEC ratings. Numbers in this classification have a significant impact on the accuracy and precision of the board’s performance.

From 1 to 9, the higher the ABEC rating, the better the bearing is. For example, ABEC 7 is faster and often more expensive than ABEC 5 products.


Bearings make your rides sharp and precise. They might be one of the tiniest skateboard parts, but they create noticeable differences in the skateboard’s performance.

Good thing that skateboard bearing dimensions don’t have as many variations as other skateboard parts. All you need is to check the shield stamps, cores, and nuts, and you’ll know the bearing size you need.

While material composition for these parts varies, it won’t matter much. As long as you have quality as your top consideration, you can expect the bearing to deliver its best performance.

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