Bike Repair Tips and Tricks

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How to best investigate what may be a bent derailleur (sh.itjust.works)

submitted 2 months ago by [email protected] to c/[email protected]

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Riding into work yesterday, somehow while upshifting my chain slipped off the smallest cog onto the frame and hopped off the jockey wheel in the derailleur - all very drastic, but it suggests to me the derailleur twisted?

Historically getting down out of the 9th or 10th gear would need 'a little extra thumb' past the shifters click, that now seems to be the case for the top few gears - but the rest of the 11 speed cluster works great still

Does this sound more like I've worn the cogs somehow or twisted / bent the derailleur?

If it was bent, I thought it would affect all shifting...

It's a shimano HG 11 speed with their reasonably recent chain that's supposed to be really long lasting (possibly intended for e bikes? Mines an old analog, mojo geometron)

I should really double check what the parts are (being a Muppet), and get a photo of the alignment, but I'd love to be able to something on my own before wheeling it into the LBS

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[–] [email protected] 1 points 2 months ago (1 children)

I can't picture a situation where this could be an issue assuming the derailleur hanger is properly aligned. The lower jockey wheel is just for tension. It has no bearing on alignment. The upper jokey wheel is the only one that matters with indexing. You might add some b-tension, if you have the room for adjustment and much slack in the chain.

[–] [email protected] 2 points 2 months ago

Thanks! I did wonder if the B tension was 'a bit off'... Well worth a look into

One classification, however: the chain did wrap off the upper jockey wheel, once caught on the frame - I hate to think what went on down there at the time