A wheel hub assembly has a group of components that work together. Each component is critical in the functioning of the entire assembly. Let’s talk about each one in more detail.

1. Wheel Hub

Wheel hub

Let’s start with the biggest part of the assembly: the wheel hub. It’s made of a forged or cast piece of metal. It resembles a disc, except it has a protruding center with wheel studs. A wheel hub has a hole in the center for the bearing assembly. In some vehicles, the bearing assembly is built into the wheel hub. In other vehicles, the bearing assembly is a separate part.

The wheel hub is an important part because it’s the “backbone” of the entire assembly. It either holds or connects the other components within the assembly.

2. Wheel Studs

Wheel stud

The wheel studs are an integrated part of the wheel hub. These studs are what connect the wheel to the wheel hub assembly. The brake rotor and wheel slide over the studs, while the lug nuts secure the wheel in place. Without wheel studs, there’s no way to connect the wheel to the hub assembly.

3. Wheel Bearing

The wheel bearing is what makes it possible for the wheel to spin. A wheel bearing is a metal ring with:

  • Steel balls or a roller element
  • An inner and outer race (metal ring)
  • A bearing cage
  • A bearing seal
  • A retainer

It’s a small part that enables the wheel to rotate freely. It fits into the wheel hub snugly, and it rides on the axle shaft or spindle. It connects to the wheel (via the wheel hub) and allows the wheel to rotate.

Out of all the components in the wheel hub assembly, the wheel bearing is the most prone to failure. It’s because the wheel bearing sees a lot of force and it is a relatively small part. If you have a hunch that you’re riding on a bad wheel bearing, this troubleshooting guide may help you.

4. Oil Seal

The oil seal is a rubber seal that protects the wheel bearings from:

  • Dirt
  • Water
  • Road debris

It also keeps the lubricating grease within the bearing assembly. Without an oil seal, the bearing assembly will deteriorate fast.

5. Dust Cap

Dust cap

Image Credit: TacomaWorld

The wheel hub assembly has an opening on the outer edge of the bearing assembly. That’s a problem because:

  • Dirt, water, and road debris can enter the opening and damage the assembly
  • Lubricating grease can leak out of the opening

There’s an easy solution. Put a dust cap in to cover the entire opening. The cap is a simple part, but it plays a big role. It maintains the longevity of the wheel hub assembly, as well as the bearing assembly.

Do you have any questions about the components within a wheel hub assembly? You can contact us here.


Stay current!

Sign up here to get the latest news
and updates on all things GMB.

Sign Up To Receive GMB News & Updates!

  • This field is for validation purposes and should be left unchanged.