Campag centaur rear mech with 29 sprocket

hammerite
hammerite Posts: 3,408
edited October 2012 in Workshop
Bought a bike for Jnr second hand which came with Campag Centaur rear mech and levers. To make it more suitable for a youngster (and potential race gear restriction) I've changed the chainset to a 33/42 with 165mm cranks and put a bigger cassette on (12-29). I've also shortened the chain (maybe it could be shortened by another link).

I read up that a 29 should be ok with Campag rear mechs, but a 30 is too big (unless going with the new Centaur compact kit). I've actually found a cassette in the garage that I used on a trip to the alps that I thought was a 28, but it seems to be a 29 and it worked fine for me with a Centaur mech.

Everything shifts ok, but it seems the jockey wheel on the rear mech and the 29 ring are touching as the chain passes through.

Is the answer to change the cassette so the biggest sprocket is a 28? Or are there any other suggestions that would move the mech away from the cassette which would mean I could still use the 29?

Comments

  • B-screw?
  • hammerite
    hammerite Posts: 3,408
    Yes, that should probably do it.

    Highlighting one the many gaps in my bike spannering knowledge!
  • Good stuff the b-screw will move the whole derailuer away or towards the cassette - I know for SRAM they reccomend a 6mm gap and AFAIK for Shimano it should be closer than that but not sure optimum distance for Campag - from the sound of it though you just need to adjust it to let your mech sit further away and if that works check you still get ok shifts.
  • hammerite
    hammerite Posts: 3,408
    Yes moving it away would be a start, let alone it being the optimum. I'll try to get an idea of how big the gap is on my other bikes with Campag as they shift fine.
  • majormantra
    majormantra Posts: 2,094
    Clearance is tight, but my Centaur (2009, short cage) mech seems to handle a 13-29 cassette ok, FWIW.
  • g00se
    g00se Posts: 2,221
    You should be able to move the jockey wheel away from the sprocket by adjusting the tension screw (the campag equivalent of the b-screw) - it's the 'rack and pinion' style screw at the top of the jockey cage. Pull the rear mech back after adjusting the screw so the mech settles into the new position.

    campy56.jpg

    However, if the mech is pre 2010, then it might not be compatible with a 29 sprocket (2010 onwards, the 10-speed rear mechs started using the same parallelogram design as the 11-speed kit).
  • hammerite
    hammerite Posts: 3,408
    Thanks for the advice. Had a fiddle last night and all seems to be working fine.

    I think the mech is pre 2010, but seems to work anyway.