Front Derailleur NIGHTMARE! (I've got blisters on me fingers!)

[Sam Kennedy]

I decided to tweak the indexing on my gears because its been playing up a bit. So I twiddled the cable tension on the rear dérailleur and had them working smoothly within 5 minutes.

With the front dérailleur, its took me 45 minutes and all that's happened is my fingers are blistered and the chain rings wont shift properly

I've played with all sorts of combinations of cable tension and H+L limits, but nothing.

So I've got a few questions:
1: The cable tension is completely off, how should I adjust it to 'start again'
2: The front shifter is a twist grip shifter, and when I twist it, it moves independently from the numbers beside it. So when it clicks it is not near any numbers.
3: Could this be a problem with the shifter and not the cable tension/limit screws?

Any help will be VERY VERY GRATEFULLY APPRECIATED!

 

[PatrickPending]

im not familiar with twist shifters but look here for fd set up:-

http://www.parktool.com/repair/readhowto.asp?id=75

there are also a few videos on youtube. good luck!

 

[Globalti]

First change the cable outer and inner; these wear and the performance gradually deteriorates. If that doesn't solve it you've exhausted the cheap options and need to spend some money - replace that twist grip with a proper shifter. Twist grips are imprecise and not durable. Your bike shop will sell you something suitable for your bike.

Unfortunately nobody makes good old thumbshifters any more, they would hve been an ideal, cheap, simple and robust replacement.

 

[Rhythm Thief]

Twist grip shifters are shite. You'd be better off manually flicking the chain between chainrings as they did back in the day. I've got a spare downtube shifter you can have if it helps you out of a hole.

 

[Sam Kennedy]

Okay I fixed it, it took me about an hour, probably more, but I don't mind because I learned a lot doing it

Since the shifter wouldn't shift down to the granny gear, and I didn't need the granny gear, I put the leaver into the second position and undid the bolt on the dérailleur and pulled out most of the slack. Then I adjusted the lower limit screw so that it would not try and push the chain onto the granny gear.

Then I had to keep fiddling with the barrel adjuster and the amount of cable going through the dérailleur bolt until it would shift into the big ring. Once I did that the majority of my time was spent fiddling the the cable adjustment and H limit screw until the chain stopped rubbing. Next time I have to do this I will make sure to loosen the barrel adjuster all the way, and only make tension adjustments with the cable going through the dérailleur bolt, and only use the barrel adjuster to fine tune it afterwards.

All in all my bike is now basically a double (could I unscrew the granny ring now since I wont use it?) and is working fine, and I have a much better understanding how dérailleurs work.

(oh, if you are wondering why I keep using the French é, it is because Firefox has a built in dictionary, and says I haven't spelled it correctly if I don't use it.)

 

[PpPete]

Hmm, my Firefox doesn't insist on the accent on derailleur, but gets all narky when I don't write FireFox with both Fs in upper case.

Frankly I prefer the french spelling of dérailleur to that stoopid American fashion of upper case in the middle of trade names.

 

[jpembroke]

For future reference, make sure you route the cable correctly at the clamp bolt. Getting it wrong i.e. clamping the wrong side of the bolt makes shifting a) very very difficult, and near impossible to index. Basically it changes the angle of leverage and throws everything out. May not have been the case with your setup but I see it all the time (mainly on road bikes though to be honest). People always assume they need new mechs or shifters when all that's needed is for the cable to undone and routed the correct way (i.e round the correct side of the bolt or over rather than under the front mech's leverage tab).

 

[NickM]

...the shifter wouldn't shift down to the granny gear...

Suggests to me that the fore-aft alignment of the derailleur cage is not quite right. Is the outer plate of the derailleur cage parallel with the chainrings when viewed from above?