How The Front Hub Works On Your Dirt Bike

How Your Front Wheel Hub Works

How The Front Wheel Hub Works On Your Dirt BikeYour front hub components are:

  • Axle
  • Spacers
  • Bearings
  • Beating Seals
  • Axle Nut
  • Pinch Bolts

Understanding how your front hub works will save you time and effort when you perform your routine maintenance!

Wheel Bearings

The wheel bearings are the most important part of the wheel hub. These are the only parts of the wheel hub that move.

The inner bearing race rides on the axle, and the outer bearing race is a press fit to the bore of the hub.

Axle In Front Bearings

The inner and outer bearing race are connected with ball bearings.

Bearings Internals

Depending on the manufacturer, some bearings come pre-greased and shielded on both sides, while others are only shielded on one side, and need to be greased before install.

Double Shielded Bearings
Double Shielded Bearings

(These particular bearings are from factory links. They are double shielded, pre-greased, and I highly recommend them. They go for $20 on Amazon.com, and you can buy yours HERE.)

Unshielded Bearings
Unshielded Bearings Need Grease

Wheel bearings are the only point of contact between the wheel and the bike, so the forces put on them are extremely high.

Because of the stress the bearings are put under, they must be in perfect working order.

Bearings do wear down, but can last for a very long time when properly installed and maintained.

When the bearings become damaged or contaminated like the ones you see here, they need to be replaced.

Damaged Front Bearings

(You can learn how to replace your front wheel bearings here)

Wheel Bearing Seals

The bearing seals keep contaminants out of the hub and away from your bearings. Compromised seals are the main cause of bearing failure. Any type of contaminant will drastically reduce the lifespan of your bearings.

Bearing Seal Closeup



Wheel Hub Spacers

The spacer between the bearings is called the distance collar, and it connects the inside bearing races inside the hub

Right Fork - Axle - Spacer - Seal - Bearing - Collar - Bearing - Seal - Collar

The spacers on the left and right of the hub connect the bearings to the axle mounts, and keep the wheel positioned on the axle.

Spacers need to be an exact length. If they are too short, your forks will bend in as you torque the axle nut. This will lead to fork binding and premature wear.

Front Axle

The axle holds all the parts of the hub, and connects them to the forks.

Front Axle

Axle Nut

The axle nut holds the hub together when mounted on the forks. The axle nut must be torqued to manufacturer specs to allow the hub to work correctly.

If the nut is too lose, the spacers and seals will spin, causing damage to the axle.

If the nut is too tight, it may warp the inner bearing race, destroying your bearings.

Pinch Bolts

The pinch bolts secure the axle to the forks.

These bolts also need to be torqued correctly, or the axle will spin in the mounts, causing damage to both the forks and the axle.

Because the axle connects the two forks, you must torque the axle nut first, then the pinch bolts on the same side.

Fork Axle Mounts

Before you torque the pinch bolts on the opposite side, you need to compress the forks several times to ensure the mounts are aligned to the axle properly.

If the forks are not aligned correctly, they will bind, and damage the fork tubes.

If you have any questions or anything to add, please leave them in the comments or on our FaceBook page!

Keep Reading – Front Wheel Bearing Change

Fix Your Dirt Bike Logo

SHARE