front derailluer fitting problem

willy-style
willy-style Posts: 52
edited March 2011 in MTB workshop & tech
I have bought a new drivetrain for my mtb... 7 speed rear cassette and chain, alivio triple chainset with 48 teeth on biggest ring, and deore m591 front derailleur.
when i have tried fitting it, according to instructions, with the outer plate a couple of mm clear of the large chainring, the inner plate rubs on the middle chainring. if i lift it higher to fix this problem, when it is in bottom gear the chain rubs along the bottom of the cage... i cant seem to find a happy medium, and have never had this problem before!
can anyone shed some light on this?
thanks

Comments

  • nicklouse
    nicklouse Posts: 50,675
    which crankset? (part number).

    what BB ? (length).
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • willy-style
    willy-style Posts: 52
    Chainset is shimano alivio m411
    bb has 122.5mm axel length, which i am told is the correct one.
    in all honesty i dont see how the bb length would make a difference in this case anyway?
  • nicklouse
    nicklouse Posts: 50,675
    just checking.

    what frame?

    it may come down to doing some bending of the cage though.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • willy-style
    willy-style Posts: 52
    Not sure what frame, it is an oldish handbuilt one.
    Do you mean bending the mech cage to make it fit better?
    sounds like a reasonable idea to me!
  • nicklouse
    nicklouse Posts: 50,675
    indeed i do.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • willy-style
    willy-style Posts: 52
    righty ho, i will have another go at sorting it, and if all else fails will do a bit of altering!
  • kja
    kja Posts: 259
    I don't think you'll have any joy fitting the M591 to a 7 speed set up, even bending the cage may not give you enough width. I bought one for my 8 speed and no amount of tinkering and faffing would get it working nicely. I've since upgraded the whole drivechain to 9 speed and the M591 now works perfectly. So sorry, but I think you'll need to get a specific 7/8 speed mech.
  • willy-style
    willy-style Posts: 52
    i see what you mean, but the mech is technically 7 speed compatable, and the problem is caused by the mech rubbing the chainset, irrelevent of chain size.
  • kja
    kja Posts: 259
    The 8 speed chainset I removed was a few mm wider than the new 9 speed one. I'm sure that's why I couldn't get it working nicely. Additionally the M591 seems to be quite an odd shape (not that I've compared many mechs!). The cage drops quite low at the back inside and I had to mount it slighlty higher than I wanted in order to clear the chainstay.
  • willy-style
    willy-style Posts: 52
    yes i had noticed it is an odd shape, and have possibly solved the problem by mounting it higher
    thanks for the suggestions!
  • kja
    kja Posts: 259
    Excellent! Glad you got it sorted. I've found it to be very reliable in use, hope you do too.

Categories