Can someone explain front mechs?

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  • Can someone explain front mechs?
  • druidh
    Member

    What model is your shifter?
    Are you running 2×10 or 2×9?

    M numbers are just Shimano Group set designations.

    Check 2 main things.

    1. Top pull (cable runs along top tube) or bottom pull (cable runs along down tube)
    2. Clamp size

    Apart from that it’s up to your budget.

    Also, see hear for Oranges advice on this

    Premier Icon Scapegoat
    Subscriber

    The M numbers refer to the model.

    The latest incarnation from Shimano XT is the M78- series. M780 is the triple version, M785 is the double, but it isn’t a double and bash.

    It looks like this :

    A M785 front mech comes in several configurations, but is double specific. The cage is the same diameter as a 40t or 38 T outer ring, and is designed to shift between a 26 or 28T inner to a 38 or 40T outer.

    The mech you linked to is a triple. It will work for your setup if you limit the mech from overshifting,using the limit screws, and find the ideal throw point, as different mechs use different amounts of cable throw to shift granny to middle than middle to outer.

    Now, the 785 is the first XT double chainset, so the M785 mechs are designed specifically to work with that.

    SLX has had a double and bash configuration, the M662 for a few years, and the front mechs are designed specifically to work with a 36/22 or sometimes 34/22 configuration.

    If your double and bash convert is nearer that configuration, then you would be better off finding an SLX M662 front mech.

    gsp1984
    Member

    I want a new front mech… I have an idea what I want, which is basically shimano xt.

    I have a 2012 orange five which is a 34.9 clamp mount. I run a triple converted to double and bash.

    But what the hell do all the M numbers mean… M770, m780, m781, m785, etc

    Would this fit?

    http://www.chainreactioncycles.com/Models.aspx?ModelID=67202

    gsp1984
    Member

    My triple is 22, 34, 44…

    I’ve ordered the first link then realised it say 42t compatible… Will this not work with my chain set? Do I need the second link?

    I’ll only be running my triple as a double, but with a gamut bash guard, is that going to be a problem, I suck at this 🙁

    http://www.chainreactioncycles.com/Models.aspx?ModelID=69397

    http://www.chainreactioncycles.com/Models.aspx?ModelID=52290

    PaulD
    Member

    You should be fine.
    Reference to 42 is that a front mech usually needs 12T difference for middle to large to work well….and you do not have a large so irrelevant.
    22 to 34 will be fine.
    Use the shifter in small and middle positions, rendering the third unusable by the limit screw on the mech.

    PaulD

    gsp1984
    Member

    Cheers PaulD and everyone else for answers, I suck at doing things myself but thought I’d give it a go. Hopefully have it running like new soon.

    Premier Icon Scapegoat
    Subscriber

    Don’t do yourself down! You’re willing to have a go, that’s the first step. The worst that can happen is that it won’t work and you’lll have to try another solution.

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