Damaged derailleur??

Pebbleheed

Hi all,

My girlfriend was out riding with me yesterday and managed to come off her bike. She survived with bruises and grazes despite a somersault but her bike took a good knock.

Since the fall the derailleur appears to be damaged. When she's peddling there's now a clicking sound and she can't select some of the gears as it no longer changes to them.

The derailleur has some scuff marks to it showing that it took a knock and got dragged.

I suspect it's bent of out of shape or moved a little, but is there a way to work out where it needs to move back to or is there a way to diagnose and fix this properly?

Not sure if I can sort this for a big ride we have planned for tomorrow or if we need to replace it?

Thanks

The Rookie

May just have a slight bend and probably just needs re-indexing, especially as it seems to be working 'nearly OK'.

cooldad

Where do you read 'nearly OK?'

Could be a damaged mech or more likely a bent hanger. The bike is a ?

Read Parktools for indexing, if that doesn't work something needs replacing, probably.

Pebbleheed

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19671446#p19671446]The Rookie[/url] wrote:

May just have a slight bend and probably just needs re-indexing, especially as it seems to be working 'nearly OK'.

Yeah, I suspect she's bent it. How do I re-index it?

Pebbleheed

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19671456#p19671456]cooldad[/url] wrote:

Where do you read 'nearly OK?'

Could be a damaged mech or more likely a bent hanger. The bike is a ?

Read Parktools for indexing, if that doesn't work something needs replacing, probably.

The bike is a BTwin Rockrider 520 from Decathlon. All standard, nothing changed on it.

The Rookie

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19671456#p19671456]cooldad[/url] wrote:

Where do you read 'nearly OK?'

I didn't, it is an interpretation of

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19671432#p19671432]Pebbleheed[/url] wrote:

she can't select some of the gears as it no longer changes to them.

Re-indexing the gears is covered by parktools, link in CD's signature, just adjusting the 2 small high and low screws and cable tension is probably all that is needed. http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur is the actual page.

Pebbleheed

I had a go at this but it didn't fix it sadly. I took it to my local bike repair shop and the cartridge has to be replaced. £35 for the part and £10 for the labour. Not too bad I suppose. And only a week or so to wait. On the positive side, the girlfriend wasn't injured.

cooldad

What's a cartridge?

mattyfez

Sounds odd, if by cartridge they mean the wheel bearings, I can't see how that would be damaged.

Either the derailleur hanger is bent or the derailleur is bent or both, the hanger is designed to bend/snap off to save damage to the derailleur and/or wheel bearing.

I have a similar issue on my bike, I've managed to bash/bend the hanger back into some kind of serviceable shape whilst I await delivery of a new hanger.

The cynic in me thinks they probably just fitted a new hanger, and possibly re indexed the gears, hangers generally cost about a tenner, so you could have been dicked for about £15. Not saying that's the case and it's not the crime of the century, but it may be worth being wary of your local bike shop, as said I can't see how there could be bearing damage without also trashing the derailleur hanger.

Antm81

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19671800#p19671800]mattyfez[/url] wrote:

Either the derailleur hanger is bent or the derailleur is bent or both, the hanger is designed to bend/snap off to save damage to the derailleur and/or wheel bearing.

How does the hanger prevent damage to the mech which is taking the impact? Or protect the bearings in the hub which are highly unlikely to be affected?

Just to clarify the removable hanger is designed to protect the frame as opposed to when it was an integral part of the frame and damage could lead to the frame being written off.

mattyfez

From my understanding and experience, the hanger prevents (ok mitigates) damage to the mech and frame by being a weak link.

I'm not saying that the mech isn't bent, it could be, but I'd also expect to see a really bent hanger in conjunction with a busted mech.

For the bearing to be damaged but with the hanger and mech seemingly ok strikes me as strange.

The Rookie

Cartridge sounds to me like a cassette...so it sounds like they think its worn and the skipping is coincidental with the crash.

cooldad

Ka Ching?

The Rookie

You are so cynical, and yeah, kind of what I thought, not much money in a straight indexing.

Pebbleheed

Yeah, sorry, they're replacing the cassette. They tried to bend it all back in shape and also replaced the cable they said was damaged but even when it was all ligned up one of the gears was still refusing to select and it was still clicking on some gears. They said they needed to order in a new cassette and replace the old one. Offered me a budget option or the original that's on the bike now.

The Rookie

Doesn't sound like a cassette issue to me.....

cooldad

Nope. Ka ching.

JBA

Unless your gf has somehow managed to bend a few teeth on the cassette I would call BS.

It sounds like a bent hanger and/or rd to me and any decent bike shop should be able to sort it out in 20 minutes.
Ask the shop how swapping the cassette for an identical one will make any difference.