Hello everyone.
Today I'm covering maintenance of the rear hub damper (cush drive) on my BMW G650GS.
The rear hub damper is a rubber cushion between the rear sprocket and the wheel.
It absorbs the shocks and vibration as the engine's power is transmitted to the wheel.
How to remove the hub damper and grease it
This is the rear wheel removed from the bike.
Remove the sprocket and rubber parts appear.
These are the hub dampers.
Remove the hub dampers.
Here they are, removed.
I apply ZOIL rubber grease to the hub dampers.
Put the hub dampers back as they were, and the job is done.
What to check on the hub dampers
Once the hub dampers are out, check the following.
- Cracks or chips in the rubber: if the surface is cracked or chipped, it absorbs shocks less well.
- Hardening or flattening: press with a finger and check that the rubber hasn't gone hard or been squashed thin.
- Play: with everything assembled, rock the sprocket back and forth by hand. If it clunks and moves a lot, the hub dampers may have shrunk.
If you feel a bigger jolt when opening or closing the throttle while riding, suspect worn hub dampers. If they are cracked or there's a lot of play, I recommend replacing them with new ones rather than just greasing them.
I showed how I replaced the G650GS hub dampers with new ones in this post (in Japanese).
Choose a grease that's safe for rubber
Some greases make rubber swell or damage it. For hub dampers, choose a grease that says it's suitable for rubber parts, like the ZOIL rubber grease (for rubber and plastic) I used this time.
I've also written up replacing the hub dampers themselves: