Just isolated an irritating squeak to a seized lower jockey wheel. Cant seem to free it up, but found a nice condition upper jockey wheel on an old derailleur. Any problems in using it? Seems to fit and work OK in the garage.

Best just use it in the garage then.

Tim,

If the good and bad one are both Shimano it will be fine.

No direct experience or comment if another brand except most of my buddies with SRAM have had the stock lower seize regularly and have replaced them with BBB cartridge bearing ones from dotbike for approx £10.

PaulD

All Shimano so perhaps I’ll live 🙂
Might be time to look up the BBB ones though

The top jockey sprockets are different from the bottom as they have lateral float to help achieve good indexing. Perhaps if both sprockets have this float then gear shifts may become a bit more wooly or the chain could jump without changing???