Save me some money...(rear derailleur)

charliew87

Hi,
Set off for a ride yesterday, made it 50 yards up the road and realised my rear derailleur wasn't working.

There was no 'click' as I tried to shift either up or down a cog. The mechanism moved minimally but then returned to it's position on the smallest cog from where it could not be moved.

I twiddled the barrel adjuster to see if that fixed the whole thing, and managed to make it move up one cog but the ability to shift gears was still beyond me.

I did a quick video this morning of it to try and help explain the issue, as you may have gathered I have absolutely no idea how a rear derailleur works I'm afraid, but don't want to spend £30 on a service if it's a common and easy fix.

http://www.youtube.com/watch?v=rKlNesy0Wrc

any help much appreciated.
cheers

greg66_tri_v2.0

Campag?

I would say that's more likely an issue with the shifter than the rear mech. The shifter on a 10s should have nine noticeable "clicks" in it before you have to hit the thumb button. It sounds like you've got one click in the shifter, and not much more. If so, it may be that a spring in your shifter has snapped.

If, on the other hand, you've got all nine clicks, then I'd guess your cable has slipped and has a ton of slack in it.

ic.

It's a Sora rear mech, not Campag

I'd imagine the cable is seized somewhere between shifter and mech.

You can undo the cable clamp on the rear mech and manually swing the mech up and down the cassette to check it if it's moving correctly. With it undone you could then check movement in the shifter.

charliew87

Yep, it's a Sora.

There's no clicking at all happening at the shifter end of things.

Will try to undo the cable clamp later...

pinarellokid

love the man cave..

id say its more the cable shifter myself also but you will need to undo that rear cable to find out more

crankycrank

Undo the cable and pull it all the way out from the front shifter. Notice if it gets stuck anywhere as you pull it out and check cable for fraying. Then thread the cable back into the shifter and housings and rather than fix it to the rear mech just pull on the cable end while shifting through all the gears. If it doesn't click your problem is in the shifter and may be cured by dowsing the shifter internals with WD-40 or some solvent, let sit for an hour or so and try shifting again. It may just be gunked up. If this doesn't work your shifter is probably broken.

charliew87

Caved and went to the LBS last night. Looks like I need a new shifter, apparently that will set me back £68!

dwanes

Run away

charliew87

...getting the new shifter. They also reckon I need another £300 worth of stuff changing so I told them to do one. Been fully serviced recently and I keep it in decent nick, or so I thought.

desweller

Haven't been able to look at the video, but:

Step A:

1) Peel back the hood on the shifter and verify that the cable tip is correctly seated and that it's not frayed
2) Verify that the cable clamp on the derailleur is tight

If those two are OK then

Step B

1) Release the cable clamp on the derailleur
2) Pull on the cable where it exits the first frame stop (usually on the downtube)
3) Operate the shifter

What this will tell you is if the cables are sticking. The shifter relies on the derailleur return spring to maintain tension in the cable; if there's a lot of friction in the cable housing runs then the cable will be effectively slack at the shifter end.

Rear shifters very rarely fail as there isn't the scope to abuse them like front shifters. Likewise derailleurs usually require specific abuse to cause this sort of behaviour. Cable failure on the other hand is relatively common; sticky cables are very common.

charliew87

DesWeller wrote:

Rear shifters very rarely fail as there isn't the scope to abuse them like front shifters. Likewise derailleurs usually require specific abuse to cause this sort of behaviour. Cable failure on the other hand is relatively common; sticky cables are very common.

How annoying!