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removing braze-on mech to mount it lower down,

brinorlbrinorl Posts: 10
edited May 2013 in The workshop
I want to use a smaller chainset, which means moving the mech down the tube, which is carbon fibre. I have bought a band on mech. Will it be possible?

Posts

  • dgunthordgunthor Posts: 644
    what chainring/chainset size are you moving from/to?

    and are you saying you are going to remove the braze-on front mech and replace with a band on?

    normally a braze-on front mech will work fine for standard of compact chainsets as it has 15mm or so of vertical adjustment, so you shouldn't need to replace it with a band on
  • brinorlbrinorl Posts: 10
    Hi, at the moment its a triple, 50 40 30, I fancy 46 36 26. I did try 46 40 30, but the mech was down as low as it would go, and although it worked, it was not as close to the biggest ring as it should be. Maybe I could try it, before going any further, its the 26, and 36 I really need, to give me low ratio,s.
  • dgunthordgunthor Posts: 644
    ah, ok. Sounds like you are trying to fit a mountain bike chainset, hence why the front mech wont go any lower.

    You could achieve the same lowering of gear ratios by changing the rear cassette - if you have a 12-23, 12-25 etc you can get up to a 27 or 28 tooth at the back without issue. Can get even bigger sprockets (e.g. 30) at the back but you may go over the limit of the rear mech then as you already have a triple chainset (it may not be able to slacken and tighten the chain over the full range of gears).

    Your lowest gear would be 30-28 with e.g. a 12-28 cassette which is a REALLY low/easy gear for the road (29 inch gear, I have a 34 inch gear 34-27 which lets me spin up pretty much any climb)
  • brinorlbrinorl Posts: 10
    have borrowed a wheel with a 12-30 from another bike, seems ok, had to change the 50 for a 48 cos chain is short, but otherwise we cracked it. thanks.
  • nicklousenicklouse Posts: 81,520 Lives Here
    Also most carbon frames that have a braze on are not standard band on sizes.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • MichaelWMichaelW Posts: 2,164
    nicklouse wrote:
    Also most carbon frames that have a braze on are not standard band on sizes.

    and most tube cross-sections are odd shapes as well.
    Bands are for round tubes.
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