Ultegra Rear derailleur not working

[corkman]

Hi,

can somebody please please please help me?

i have an ultegra group which has been giving me trouble for some time now, the rear mech either won't stay tuned or is nigh on impossible to tune. 2 year old canyon

History: hanger got bent, mechanic fitted a new hanger and new cable and tuned up a few weeks ago, everything was fine until I removed back wheel when washing bike, put back on, out for a ride and not changing properly again (mostly shifting down), tried to tune it again but cannot get it right. If i do happen to get it right on stand it doesn't shift properly when I actually ride the bike.

There is something else obviously wrong here and I have been through 3 bike mechanics/bike shops (and a lot of cash) so have no confidence that going to another one will get me sorted. Last mechanic checked everything else on bike when hanger was fitted and was happy with chain, cassette etc.

Please help and feel free to ask any questions

[Brucey]

the shimano website used to have a page called '101 causes of bad indexing' so there are plenty of possibilities here.

All you can do is to check the rear mech condition and alignment, check that the cable is OK (they often fail inside the STI itself) or better still replace the cable.

If you have the non-washing line type STIs (ie with the cables under the bar tape) then they are much more likely to suffer problems with cables that are just slightly bad for some reason.

The other thing to bear in mind is that if you ride your bike much, after two years your cassette and chain will be kippered anyway; you may need some new parts.

I thoroughly recommend learning how to sort this stuff out for yourself. You need deep pockets if you are going to pay a bike mechanic to do everything for you.

cheers

[PJ520]

I was having similar problems, a couple of LBS's swore he rear derailer was adjusted right, I'd ride it a few miles and the indexing was off. I took it back to the last LBS and this time the guy actually rode the bike rather than mess with it on a stand. I don't know why but that allowed him to diagnose a worn cable housing, changed that and it fixed it.

[corkman]

Brucey,

Thanks for reply, the cable has been replaced as I mentioned and the mechanic did mention the two year timeframe for parts like you said so maybe its time to dig deep again. I have suspected that the derailleur may be damaged from when hanger got bent, might just replace sprocket also. I totally agree with learning this stuff yourself. Being an engineer it shouldn't be a big ask for me!

[corkman]

Pete,

Thanks, that's more or less what I have been experiencing, fine on stand but not when ridden. Words of caution for anyone reading this forum. I don't understand why LBS' don't test ride a bike after servicing. Last mechanic is going to call back to look at bike which gives me confidence in this guy. I'm gonna watch him this time and learn something as Brucey suggests

[pete75]

Brucey,

Thanks for reply, the cable has been replaced as I mentioned and the mechanic did mention the two year timeframe for parts like you said so maybe its time to dig deep again. I have suspected that the derailleur may be damaged from when hanger got bent, might just replace sprocket also. I totally agree with learning this stuff yourself. Being an engineer it shouldn't be a big ask for me!

If you're going to do that you may find this helpful http://www.parktool.com/blog/repair-help

[corkman]

Brucey,

Thanks for reply, the cable has been replaced as I mentioned and the mechanic did mention the two year timeframe for parts like you said so maybe its time to dig deep again. I have suspected that the derailleur may be damaged from when hanger got bent, might just replace sprocket also. I totally agree with learning this stuff yourself. Being an engineer it shouldn't be a big ask for me!

If you're going to do that you may find this helpful http://www.parktool.com/blog/repair-help

Thanks pete!

[Brucey]

I second that suggestion!

BTW since cable problems are so commonplace I would still advocate checking it carefully even if it has been recently replaced. If the cable housings are worn (or badly prepared) then the cable inner itself can be brand new and it still won't work properly.

Some mechanics refuse to use lubricant on inner cables; IME set up this way this arrangement lasts about five minutes before it stops working properly. Whilst it is important to use the right stuff, using nothing (on shimano systems) is a bit mental.

cheers

[corkman]

So that begs the question, do I need to find a good experienced bike mechanic in the East Yorkshire area, anybody know of one? What annoys me also is that I told each mechanic all the history of the bike in order that they could properly diagnose what was wrong and if I did have to pay out it would be cheaper (and much quicker).

Its just so frustrating when your out riding and the problems show themselves up!!!!!

[pete75]

East Yorkshire - are you far from York? The guys at York cycle hub know what they're doing and don't charge for diagnosis and estimates. They're a charity set up to restore old bikes for use and to promote cycling in general. http://www.bikerescueproject.org.uk/hub-station/

[corkman]

East Yorkshire - are you far from York? The guys at York cycle hub know what they're doing and don't charge for diagnosis and estimates. They're a charity set up to restore old bikes for use and to promote cycling in general. http://www.bikerescueproject.org.uk/hub-station/

Cheers pete!! Only 40 mins from York!

[Dave W]

My rear shift change started to go funny recently seemed to change up ok but not back down I could adjust the cable and get it spot on for a while then off it would go again. Last week the cable snapped inside the shifter - problem solved, frayed cable must have been snagging in the outer housing.