Do I need a Compact front mech?

Discussion in 'Bicycle Mechanics and Repairs' started by slow down, 21 Nov 2007.

  1. slow down

    slow down New Member

    Thinking of switching one of my bikes to a compact chainset, currently Campag Veloce 39/53 with a 12-25 cassette. If I swap to a 50/34, do I really need a new front mech (or a medium cage rear mech for that matter), or will the standard mechs cope?
  2. TheDoctor

    TheDoctor Resistance is futile! Moderator

    Received wisdom is that the standard mech works fine, but the compact one is a little smoother. Can't speak for the rear mech, but you're only asking it to wrap an extra few links of chain, so I'd try it and see.

    I expect someone who's actually done this with Campag will be along soon. I've only done it on Shimano (taking a 52/42/30 set to 48/38/24).
  3. Dave Davenport

    Dave Davenport Legendary Member

    Shouldn't be a problem using existing mechs.
  4. yer it will all work but you might need to move the f mech down by ? 4, 5 mil if it rubs.
  5. Smokin Joe

    Smokin Joe Legendary Member

    I've just switched from using a mid-nineties 105 front mech to the new Campag combined thingy on a Centaur compact.

    Bugger all difference.
  6. fossyant

    fossyant Ride It Like You Stole It!

    South Manchester
    Front mechs are usually same except those for 3 chain rings, then there might be a difference - i.e. more travel.

    You'll need to move the mech up or down the down tube so there is about 3mm clearance of the cage to biggest chain ring.
  7. Shouldn't be a problem. I did exactly the same and all I had to do - apart from fitting compact chainset - was reposition front mech slightly and take a couple of links out of the chain.
  8. Membrane

    Membrane New Member

    Which Shimano range offers a 48/38/24?
  9. TheDoctor

    TheDoctor Resistance is futile! Moderator

    Any of them once you've changed all the rings!:blush:
    It was actually a Sora. And yes, I did change all the rings. It's not a facetious reply.
  10. Membrane

    Membrane New Member

    Ah, right. I was wondering because that 24T difference falls outside of Shimano specifications (they are specified up to a 22T difference).
  11. TheDoctor

    TheDoctor Resistance is futile! Moderator

    Indeed. I actually wanted a 26T inner ring, but the LBS had run out. I'm using a 13-26 cassette, and a 25" bottom gear struck me as being a little overkill. Having said that, it came in handy in the alps and North Wales.
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