How Your Front Wheel Hub Works
Your front wheel hub components are:
- Bearing Seals
- Axle Nut
- Pinch Bolts
Understanding how your front wheel hub works will save you time and effort when you perform your routine maintenance!
The wheel bearings are the most critical 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 wheel hub.
The inner and outer bearing race is connected with ball bearings.
Depending on the manufacturer, some bearings came pre-greased and shielded on both sides, while others are only shielded on one side, and need to be greased before install.
(These particular bearings are from factory links. They are double shielded, pre-greased, and I highly recommend them. They go for $20 and you can buy yours HERE.)
Wheel bearings are the only point of contact between the wheel and the bike, so the forces put on them are incredibly high.
Because of the stress the bearings are put under, they must be in perfect working order.
Wheel 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.
(You can learn how to replace your front wheel bearings here)
Wheel Bearing Seals
The bearing seals keep contaminants out of the wheel hub and away from your bearings. Compromised seals are the leading cause of bearing failure. Any type of contaminant will drastically reduce the lifespan of your bearings.
Wheel Bearing Spacers
The spacer between the bearings is called the distance collar, and it connects the inside bearing races inside the wheel hub
The spacers on the left and right of the wheel 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.
The axle holds all the parts of the wheel hub and connects them to the forks.
The axle nut holds the wheel hub together when mounted on the forks. The axle nut must be torqued to manufacturer specs to allow the wheel hub to work correctly.
If the nut is too loose, 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.
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.
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!