Best way to secure hub-mounted sprocket?

Engineer

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As you all may already know, the installation for hub-mounted sprockets is pretty straightforward. But seeing as the surfaces of the hub itself and adapter are smooth, I don't see them able to adhere to one another securely, even with substantial tightening. Therefore I'm trying to figure out the best way to secure the sprocket so there isn't any possible slippage between the adapter and hub (or axle) caused from the torque of the motor.

Since I haven't found much of anything relating to the thesis of this topic through loose research I figure we could all come up with some sort of solution to eliminate the chance of slipping over time.

Brainstorming / R&D:

- Metal shim(s)
- Strip of innertube rubber between hub and adapter to increase grip
- Scoring the metal of hub and adapter (without ruining the integrity of either)

What I've listed are just ideas, not suggestions or sure-fire solutions. If you creative lot have tried anything that's worked exceptionally or have thought up a method you think is useful, feel free to share. :D
 
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I've tried the strip of innertube rubber, it worked only to an extent. After a couple dozen miles it began to tear and somehow slipped from underneath the hub adapter. In conclusion, it failed.
 
just crank down hard on it, you'll wreck your tool before you damage the threads. I've got around 1500 miles on my hub adapter without failure
 
The clamping force of the adapter is plenty enough to keep it in place, as long as it's the right size for the hub and you've tightened it enough, as butre said.

Using any kind of shim is unnecessary (and not recommended) and you do not need to score the mating surfaces.
 
green loctite will probably hold it if you never need to take it off again
 
don't know if it has changed, but in the 60s I knew an old mechanic that put crank cheeks back together with green & they were close to welded
 
I sandwiched my sprocket so the sprocket is in the middle of the rubber clamps & the hub is through the hole. I had to bend my brake arm further but now I know my sprocket is on perfectly. I also got some lock nuts & better quality bolts because I don't trust using cheap bolts with all metal lock nuts.
Here's how it looks:

IMG_4430.jpg

I had to get creative to make the coaster brake arm fit back on the frame with a bracket I found & some bolts.
 
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Did you use three rubbers? Metal on spokes usually cuts them pretty quickly.
 
I sandwiched my sprocket so the sprocket is in the middle of the rubber clamps & the hub is through the hole.

View attachment 57911
This topic is about securing a specialty clamshell hub sprocket adapter directly to the hub, not the 'rag joint' sprocket.

I do however need to point out that this is an example of how NOT to install a kit sprocket.

The sprocket itself is one side of the mount, nothing goes on the outside of the sprocket.
Those 'rags' which are actually circles cut out of recycled tire sidewalls, are meant to sandwich your spokes and hold them.
The metal plates are used to form a circle around the inside 'rag' for the bolts to go through from the sprocket and secure the whole sandwich together.

RagJointSprocket.jpg


By tightening the 9 bolts in a star pattern you bring the outside metal parts together and the rubber forms itself around the spokes.
I find this a better method if done right that any clamshell hub, it doesn't have grip the hub directly and does provide a bit of 'shock isolation' between the engine and back wheel.

In short bikejock, having a set a metal rings and a rubber rag joint on the outside of the sprocket does nothing good, the sprocket itself is already one side of the sandwich to begin with.

Having your sprocket right up against your spokes and only one rag inside will cause your sprocket to not stay true which in turn is going to cause metal to metal wear on your spokes with the wobble, and of course eventual failure.

If a dust cover is in your way, toss it, just oil that spot regularly.
If the brake arm don't clear the bolt heads bend it, I find a vice and a big crescent wrench works well for this.

Not trying to 'rag' on you bikejock, you are a good guy, but that is not a sprocket mount to be proud of bud hehe ;-}
 
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