Do I need a new front mech?

Plisskeniscool
Plisskeniscool Posts: 3
edited August 2014 in MTB workshop & tech
Just getting back into biking after a few years and am replacing parts on my old trek mountain bike. I've just swapped old octalink BB and fitted new shimano hollowtech crankset triple with the external BB. I'm finding I can't get the front mech to engage the biggest chain-ring. In fact, even pushing the mech with the cabling undone doesn't seem to move it far enough out. Do I need a different type of mech for this setup, or have I messed up the installation of these cranks so that they are too far out? Thanks in advance for any help.

Comments

  • cooldad
    cooldad Posts: 32,599
    Have you adjusted the high limit screw?
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  • paul.skibum
    paul.skibum Posts: 4,068
    One set of cranks to another do not necessarily put the chainrings in the exact same position so the front mech will need adjusting to make for smooth gear shifting.

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  • Plisskeniscool
    Plisskeniscool Posts: 3
    I lubed the mech thouroughly and was able to coax it over the big chainring. The H limit screw was fully out, ie not threaded, Adjusted and all was going okay until I need to shift back off the big ring and the mech stuck in place. Releasing the cable made no difference, until I completely undid the cable bolt and the mech snapped back. Tried this a few times same result. Have knackered 2 cables clamping and unclamping. I'm thinking the answer to my original question is yes unless someone has an idea.

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