- Member29 May 2018 at 11:51 am
At the weekend I did a rear cassette, chain and jockey wheel change. Whilst cleaning the derailleur cage a small piece of metal broke off (as in photo). The result was that the rear derailleur mech is constantly jumping back and forward, and the chain is jamming around the front chain ring. I backtracked and put the original jockey wheels back on however the problem remains. Is it possible that the metal broken from the derailleur cage is causing this? I thought it was just a guide but perhaps it acts as something to do with tension? Any help greatly appreciated.
- Member29 May 2018 at 6:44 pm
Providing that the break was clean, and the break is outward facing I wouldn’t have thought that it would be having the effect that you are experiencing, I would have expected things to running quite smoothly still.
It’s an odd thing to occur when replacing all new bits, the jockey wheels were a “like for like” replacement i take it. ❓
The rear mech is still straight and hasn’t been bent has it. ❓
- Member30 May 2018 at 11:06 am
Could be that the chainrings are worn and the new chain doesn’t match its pitch.
put a light behind it and put some tension on the crank and observe how the chain is sitting on the ring
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