Shimano parts always match?

SDWcp
SDWcp Posts: 9
edited June 2007 in Workshop
I've just swapped my 105 chainset for a new Shimano compact and bottom bracket. Seems I now get slight chain rub on the inner ring and biggest cog on the back. The shop says they've tried everything but it won't run without some rub - the chain comes off if they move it any further.

It was fine before until fixing the compact - should Shimano parts match up exactly?

Comments

  • combat_wombat
    combat_wombat Posts: 2,188
    are you mixing 9 and 10 speed components?
    48/19 Winter : 105 Summer
  • overweightandunderpaid
    overweightandunderpaid Posts: 92
    Mine did....have you changed the chain length/tension? also, as the rings are now smaller, the chain is at a different angle in two planes and in a different position, so play with the position of the front mech. You should be able to sort it so long as there aren't any restictions to moving the mech on the frame or braze-on mount.
    Dave
  • sjcpcp
    sjcpcp Posts: 604
    It could be one of many things. The most obvious would be chain length or front mech adjustment

    Both the chainrings are smaller than the ones that where originally on the bike, so the chain will now be too long.
    The front mech should clear the big chainring by 3-5mm, it will now be too high because you're running smaller chainring and will therefore need lowering, although if you lower it you may then have to re-clamp the cable as the cable may become too slack to correctly index the front mech.
  • SDWcp
    SDWcp Posts: 9
    The shop fitted it for me. It is a 10 speed compact but on a nine speed - I was told there should be no problem in this.

    They said they fiddled around with the front mech etc but couldn't make it go further without the chain coming off the inner ring.

    Bit puzzling all round!

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