Campag front mech phantom change

dabber
dabber Posts: 1,937
edited September 2012 in Workshop
I've got an occasional problem with my Record (10) suddenly changing from large chainring to the small (50 to 34)
when I change to a larger rear sprocket (Veloce).
Typically, I might be going hard (for me) in a Large to Small setup, then needing to go up a rear sprocket or two and finding the front had jumped from 50 to 34.
I'm pretty sure it isn't me knocking the LH button by mistake. It doesn't happen often and all changing, front and back is otherwise excellent.

Any thoughts?
“You may think that; I couldn’t possibly comment!”

Wilier Cento Uno SR/Wilier Mortirolo/Specialized Roubaix Comp/Kona Hei Hei/Calibre Bossnut

Comments

  • Monty Dog
    Monty Dog Posts: 20,614
    Unscrew the top stop screw on the front mech a touch, - it may be that the shifter isn't quite clicking into the top positon otherwise the internals of the shifter may be worn.
    Make mine an Italian, with Campagnolo on the side..
  • g00se
    g00se Posts: 2,221
    I found this happened when I was in the big ring's inside trim position (ultrashift) when the front mech was mis-adjusted. I think the front mech's position allowed the chain to drop when it should have still prevented it (possibly a bit of flex in the BB starting the fall).

    Hopefully, it'll just be a matter of a little more tension in the cable, but it could be that the front cage is a touch too high or the rear of the cage is a little pushed in. So it might be an opportunity to get the Campag tech docs and have a go at setting the front mech up as per the official instructions.
  • dabber
    dabber Posts: 1,937
    Thanks for the suggestions. I tried Monty Dog's suggestion of adjusting the high gear limit adjuster screw. I backed it out half a turn before I went for a ride this morning. I did just over 50 miles and there were no problems so ... hopefully... crossing fingers.

    Just seen your suggestions g00se when I got back... I'll bear those in mind. Thanks...
    “You may think that; I couldn’t possibly comment!”

    Wilier Cento Uno SR/Wilier Mortirolo/Specialized Roubaix Comp/Kona Hei Hei/Calibre Bossnut