I know you can rebuild the shifters, but can you service the derailleur for this particular problem?
It's a Campy Chorus rear derailleur from 2006. Last summer I was with a group. We went around a right hand turn. There was oil on the road and I came down on my right side - hard, but not too hard. A few scrapes on my body and a lot of road grime. Everything seemed ok on the bike. It shifted fine and I finished my ride.
Over the last few months my shifting seems to be getting worse and worse. I had 2 mechanics (good ones) look at the bike and the could not find the cause. The bike needed a new chain plus I put a new cassette anyways so I just had ths doen about 2 weeks ago. 11x23 if that means anything to this story. The shiftng has become far worse.
Last Friday night, I was watching a movie while playing with the derailleur adjutment trying to come to some solution. It was then I discovered that I could get the derailleur adjusted so it would either upshift smoothly or downshift smoothly BUT NOT BOTH! Visually everything was OK. Nothing looked out of whack.
Then I noticed the side of my derailler had a healthy scratch on it. Presumably this was from the wipe out several months before. Upon closer inspection I discovered that the part of the derailer that is bolted to the frame, where one of the springs lives, was a little wobbly. Bear with me as i try to explain this part: This is the part where the derailleur bolts to the frame. It looks like a cylinder that sticks out from the frame by about 1 inch. it attaches to the first moving part of the deralleur. it appears there is either a bearing or a bushing built in there that has gone bad giving it the ability to wobble just enough. I would guess it cause the first pully to deflect 5 degrees or so. I have two other bikes and neither derailleur has ANY wobble. They shift fine.
Question #1 Can that part be serviced, or am I getting a new derailleur?
Question #2 Do you guys think that something else might be wrong? How can I check? The frame has no sign of having been bent - but I am not sure I could tell. The hanger and everything else in that area are firmly attached and show no signs of trauma. The only "wiggly" part is the one I described above.
Question #3 Should I just buy a new derailleur and see if that works? This is an expensive way to "test" my theory.
Question #4 Does it sound like there is more going on and I should start looking for a new bike???