scotsbikester
Senior Member
Long (ish) story. My RD is XT-M772 SGS (the long cage one). Front is, er, I can't remember, some sort of Shimano triple. Wrestling the rear wheel off last night I think I bent my rear derailleur. Sequence of events is this:
1. Needed to take rear wheel out. Difficult, as tyre catches chainstay bridge mudguard bolt. Lesson learnt - deflate tyre first. Also my rear wheel removal technique needs improving. Anyway, it was late, and dark, there was much huffing and puffing.
2. Got it out, did what I wanted to (new disc pads). As I'd broken the chain, took opportunity to take cassette off, clean etc. Wheel back in, new chain on. Rear derailleur untouched, except for cleaning crud off guide and jockey wheels.
3. All back on. No way could I get it to index properly. I hadn't changed the cable tension - the cable wasn't unclamped, the adjuster wasn't touched. Endless fiddling, still couldn't get it to index.
4. I happen to have several spare XT-M772s. I put another one on, used but good. With only the most basic set-up it indexed perfectly. Had to do a bit of fiddling with the B-screw to get the guide wheel out of the way in big-big (not that I'll ever use that).
My conclusion is that the hanger isn't bent, but the "duff" derailleur is. I actually have two NOS new in box derailleurs, so tried to compare it to one of those. But the shape of a derailleur makes it hard to judge - lots of things at different angles.
Is my conclusion correct? That it's the derailleur itself, rather than the hanger? My simple "test by substitution" would suggest yes.
And I assume that the only part of a derailleur that can really be bent is the cage. Is that correct? Given this is "old" kit, I'm tempted to buy a new pair of cage plates, if that's all it takes to get it back to good working condition.
Any suggestions gratefully received.
1. Needed to take rear wheel out. Difficult, as tyre catches chainstay bridge mudguard bolt. Lesson learnt - deflate tyre first. Also my rear wheel removal technique needs improving. Anyway, it was late, and dark, there was much huffing and puffing.
2. Got it out, did what I wanted to (new disc pads). As I'd broken the chain, took opportunity to take cassette off, clean etc. Wheel back in, new chain on. Rear derailleur untouched, except for cleaning crud off guide and jockey wheels.
3. All back on. No way could I get it to index properly. I hadn't changed the cable tension - the cable wasn't unclamped, the adjuster wasn't touched. Endless fiddling, still couldn't get it to index.
4. I happen to have several spare XT-M772s. I put another one on, used but good. With only the most basic set-up it indexed perfectly. Had to do a bit of fiddling with the B-screw to get the guide wheel out of the way in big-big (not that I'll ever use that).
My conclusion is that the hanger isn't bent, but the "duff" derailleur is. I actually have two NOS new in box derailleurs, so tried to compare it to one of those. But the shape of a derailleur makes it hard to judge - lots of things at different angles.
Is my conclusion correct? That it's the derailleur itself, rather than the hanger? My simple "test by substitution" would suggest yes.
And I assume that the only part of a derailleur that can really be bent is the cage. Is that correct? Given this is "old" kit, I'm tempted to buy a new pair of cage plates, if that's all it takes to get it back to good working condition.
Any suggestions gratefully received.
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