I've got a Campagnolo Chorus 2x9 drivetrain on my bike. Lately I've found that shifting to the big ring is very difficult: The only way to get it to shift at all is to make a simultaneous front and rear shift going little>big and big>little; I assume that this introduces slack into the chain to make the shift easier. This isn't always successful, and when it is, I wind up overshifting (which is easy enough to correct, happily).

It hasn't always been like this. Not sure where to begin diagnosing the problem.

  • Have you recently replaced the cables+housing? Is the cable moving freely? Have you tried lubricating the FD? – Batman Sep 5 '17 at 23:02
  • Cable is moving freely. Have not changed cables or housing lately. Have not tried lubing FD, but will give that a shot. – Adam Rice Sep 5 '17 at 23:05
  • If you operate the cable by hand, does it require excessive force? – Batman Sep 5 '17 at 23:36
  • First, clean and lube your cables. Then adjust the derailer limits, especially the high limit. (As an experiment, try operating with the high limit loosened a hair.) But if the bike has a bunch of miles on it then it's likely that the chain or chainring is worn out. – Daniel R Hicks Sep 6 '17 at 1:07
  • I've never used Campagnolo, but when I have problems shifting to the big ring, If no changes have been made to the bike, I check cable tension. If there is too much slack I tighten. If that does not solve the issue, I check whether 1) the crankset is well seated into the bottom bracket axle, 2) All chainring bolts are in place and tight 3) the chainring is not deformed. – Jahaziel Sep 6 '17 at 1:42

This problem developing over time starting from it working well implies a cable gone slack (not really probable with old left Ergos because they usually have cable pull to spare) or derailer pivots that have gotten too sloppy to shove the chain with the right level of assertion. If the front derailer got shoved out of position or bent due to chain jam or other trauma this could also result. Errors in FD position or limit screw position could also cause this.

Grab the tail end of the FD cage and wiggle it firmly to see how its doing on slop. It should be negligible. Check for any tweaks of the cage or broken bits. If it looks good then go through and adjust all aspects of the FD - position, limit screws, and cable tension, in that order.

A severely worn chain or worn ramps/pins could degrade shifting enough that you get this issue, but aren't typically the root cause.

  • I swapped in a big ring with one more tooth than the old, and it made a huge difference changing up at the front. – Criggie Sep 6 '17 at 7:57
  • 9-speed Chorus was discontinued about 15 years ago. Those CNC chainrings last a long time but I wouldn't be surprised if it was worn out. – ojs Sep 6 '17 at 10:36

I appreciate all the responses. In this case, cable tension seemed good, and actuation seemed responsive. The derailleur seemed pretty clean but I degunked it just to be on the safe side.

What seems to have fixed the problem is rotating the derailleur on the seat tube--it's a clamp-on mount, not a braze-on mount. I wound up adjusting the rotation by few degrees clockwise (looking down from above).

I'm at a loss to explain how it got rotated out of position in the first place. I don't see any signs that it was. It may be that the cage got slightly bent in transport at some point, and rotating it is compensating for the damage but not fixing it. Hard to say because the cage sideplates are not flat or parallel.

In any case, front shifting is working fine now. No overshifting. The front mech does require attentive trimming.

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