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Repairing a second hand hub
#1
I got a second hand hub on Ebay recently that was listed as for spares or repair, has a slight oil leak. When I got it the leak was a bit worse than slight ,the whole drive side was covered and it was running down the spokes. Further investigation revealed that the freewheel had also been completely destroyed. Not only had the pawls broken but somebody had really tried to continue riding. Some of the pawls have been reduced to the size of grains of sand and in the process gouged the tops off the ratchets.

[Image: P1010281_zpse3254964.jpg] [Image: P1010285_zps8e7109f0.jpg]
[Image: P1010303_zps46adce3c.jpg] [Image: P1010297_zps3b9f9d69.jpg] No wonder the seal leaked.

I don't understand why some people have to be so rough with the freewheel when there is such good control possible over the ratio. Why go from freewheeling to stamping on the pedals. So far I haven't managed to destroy one. I tend to slow my cadence right down and pedal gently instead of freewheeling unless on a long decent. Better for blood circulation and the freewheel is engaged ready for transmitting power when needed.

I striped the hub down to give it a check inside and replace the internal half of the freewheel. It looks OK, has probably done around 1000 miles maybe more judging by the traction fluid and the amount of stator wear. One thing I noticed about the stator wear was that it is more even along the slot instead of concentrated towards the underdrive end like on my hubs.

For the moment I have swapped the freewheel parts from the test hub. I also replaced the leaking seal. Although I think the leak was due to a metal particle under the seals lip, I found a few in the area.
The only other issue I found was a few large particles of aluminium which I discovered had come from the tabs that hold the large driveside bearing in place. Not sure why some of them broke off. I removed most of them from the traction fluid.

With the hub already built into a wheel I fitted a tyre and took it on a test ride. To start with I felt a few particles get crushed when in underdrive heading up hill. After that it performed perfectly, well worth fixing. It's in better condition than the test hub so I should be able to get a few thousand miles out of it. The leak has reduced enough to not show any signs after 10 miles.

I'll be checking Ebay frequently for any more like it.
- Oran
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#2
WOW! Nice pick man!

I should try to find one to for experimentation!

It would be great if the ring holding the spokes could easily be removed from the bub... This way, no lacing required when changing or maintaining the hub!
I'll have a look at a second hand hub and see if I could give it a pass on a lathe to modify it!
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Si ça a déjà été fait, je peux le faire
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#3
That's an interesting idea making the transmission removable from the wheel hub. Not sure about modifying a hub it sounds like as much work as building a wheel. Every new hub would have to be modified.

Making a large hub that an entire unmodified NuVinci hub could fit into would be a useful thing. It would need a removable flange on one side and pins to engage with the NuVinci's spoke holes.
- Oran
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