MTB front mech

thiscocks
thiscocks Posts: 549
edited November 2012 in MTB workshop & tech
Hi,
A friends bike needs a new front mech as I have tried to adjust it but it wont go onto the large chainring, so I think its bent. I have set up some road bike front mechs but this one looks a bit odd so I dont know which to get.

It is quite an old Shimano Altus, and looks like it fixes to the BB. Its a 7 speed gear set.
Pics:
mech3.jpg
mech1.jpg
mech2.jpg

Anyone know what one I need to order?

Thanks for any help,
T

Comments

  • benpinnick
    benpinnick Posts: 4,148
    You have an e type mech currently, but for no good reason. You'll need to remove the bob cup to take it off. To replace, either an etype of similar spec, or my preference would be a band on mech with down pull. There's so many options , plus you need the right size... I think it's probably bike shop time.
    A Flock of Birds
    + some other bikes.
  • cooldad
    cooldad Posts: 32,599
    By bob I think he means bottom bracket.
    I call mine Ralph.
    I don't do smileys.

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  • The Rookie
    The Rookie Posts: 27,812
    There may be a good reason like non standard tube diameters......

    why won't it go onto the top chainring, what have you done to try and fix it....have you setup and indexed front mechs before?
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • Thanks for replies. Well the cable was already tight on the bottom ring but it wouldn't index up to the top. I tightened it literally as tight as I could(never had to do before on other mechs) on the bottom ring and it did just click up to the big ring but wouldn't shift over far enough to stop rubbing on the outside of the chain... the limit screw is wound right out, so It's not that. The spring looks slightly bent and the whole mech seems to move a fair bit on the mounts to the bb so I assumed something is inherently wrong with the unit... any ideas?

    If I need another, searching for etypes, would something like this work with 7 speed?

    http://www.google.co.uk/shopping/produc ... c:overview

    Cheers
  • jimothy78
    jimothy78 Posts: 1,407
    If you want to try replacing the mount, I have an e-type Altus 6/7/8speed mech (FD CT91) I removed from my bike when I upgraded to 9-speed. It's the top-pull variant, but the mount is the same, and attaches to the upper part of the mech with two bolts, so you should be able to swap it over.

    Give me a pm if you're interested.
  • nicklouse
    nicklouse Posts: 50,675
    thiscocks wrote:
    Thanks for replies. Well the cable was already tight on the bottom ring but it wouldn't index up to the top. I tightened it literally as tight as I could(never had to do before on other mechs) on the bottom ring and it did just click up to the big ring but wouldn't shift over far enough to stop rubbing on the outside of the chain... the limit screw is wound right out, so It's not that. The spring looks slightly bent and the whole mech seems to move a fair bit on the mounts to the bb so I assumed something is inherently wrong with the unit... any ideas?

    If I need another, searching for etypes, would something like this work with 7 speed?

    http://www.google.co.uk/shopping/produc ... c:overview

    Cheers

    looking at the wire i would be removing it (as it needs replacing any way) and then see if you can move it by hand to shift into the big ring. and if not see what is catching or worn.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The Rookie
    The Rookie Posts: 27,812
    Did you wind the right stop out?
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • Did you wind the right stop out?
    ^this.
    There is high and low limit screws (labeled H & L), if the H screw is in too far it will stop the derailleur moving all the way up (this is is job, to stop it going too far)