I have this problem shifting a Campy 11 that I cannot seem to rid of.
These are Campy Record 11 speed (pre 2015) shifters with a Campy Chrorus rear derailleur.
Here is what is happening:
1) When the chain is at the middle of the cassette when I shift up the cassette, the shift lever clicks, the rear derailleur moves, but the chain does not move. I have to move the shift lever just slightly to get the chain to move up.
2) If I shift and I hold the lever in place waiting for the chain all is OK. So move the lever, hear the click, wait for chain to move, then release. This is different from just moving the lever, hearing the click and letting go. But not exactly ideal..
What have I done to try and fix this:
1) Replaced cables and housing twice.
2) Changed the chain
3) Swapped cassettes
4) Changed frame (it had cracked so I got a new one)
The only thing I haven't changed are the levers themselves..
What I have noticed is that when I move the lever and hear the click and let go, I can actually see the derailleur move slightly back down again. I suspect it's this slight move down as the cable loses tension that is causing the chain to not move up the cassette. If I hold the lever, this gives the chain time to move up.
Any ideas what's going on ?
One option is to just replace the levers. But since this is pre 2015, my understanding is I will need new levers and a new rear derailleur.
BTW, these levers always did this.. Going on 4 years now. It's just now that I got fed up with it.