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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

    Location:
    Walsall
    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 Man-Machine Staff Member

    Location:
    Stevenage
    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 Guru

    Location:
    Hampshire
    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!

    Location:
    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 Man-Machine Staff Member

    Location:
    Stevenage
    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 Man-Machine Staff Member

    Location:
    Stevenage
    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.