How Your Rear Wheel Hub Works
Understanding how your rear hub works will save you time and effort when you perform your routine maintenance.
Unlike the front hub, the rear has three bearings instead of just 2, and a bearing retainer that screws into the brake side of the hub.
There are two bearings on the sprocket side and one bearing on the brake side. The double bearing on the sprocket side is needed to handle the torque from the engine.
Wheel Hub Components From Sprocket To Brake Disc
|(Click To Enlarge)|
|Left Axle Spacer|
|Left Bearing Seal|
|Left Outer Bearing|
|Left Inner Bearing|
|Right Bearing Seal|
|Right Axle Spacer|
|Washer And Axle Nut|
Rear Axle Assembly
The square axle end and axle block allow the rear wheel hub to slide up and down the swing arm when adjusting the chain tension.
The rear brake assembly mounts to the axle and rides along a track in the swingarm, so it stays in place when the wheel moves during chain adjustment.
Rear Wheel Bearing Stack
The bearings are the only part of the wheel hub that spins and are the only connection between the hub and the axle.
(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.)
The spacers and bearings must all be an exact length, so the swing arm is not pulled together, or pushed apart. If any component of the wheel hub is damaged or out of spec, it needs to be replaced.
While not part of the axle, the chain adjustment bolts are critical.
These bolts keep the wheel aligned perpendicular to the drive chain. If the rear wheel is out of alignment, it will cause premature wear on the drive chain, sprockets, swingarm, and bearings, all of which cost money to fix.
The axle nut must be torqued to proper specification to allow the components to work together. Too tight and you will foul the bearings, Too loose and the spacers will spin on the axle.
When the wheel hub components are in good shape, greased up, and aligned properly, your rear wheel hub can go years without maintenance.
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