Front Mech Won't Shift Up

mark8191
mark8191 Posts: 78
edited September 6 in Workshop

Hi all,


The front derailleur on my gravel bike stopped moving up into the big ring. The bike has no barrel adjuster for the front derailleur. I tried undoing the cable bolt and pulling the shifter cable taught and retightening but this did not work/ made the shift worse. I can only think that there is still some slack somewhere in the cable

Any thoughts on where I have gone wrong?


Thanks

Comments

  • Wheelspinner
    Wheelspinner Posts: 6,711

    Simple test: undo cable bolt on the derailleur so the cable is free. Hold the end of the cable taut-ish with fingers or pliers and operate the shifter as normal. You’ll easily feel if the cable is moving freely or not.

    If it does move freely, your FD limit screws may have crud stuck in them or just gummed up pivot mechanism, or be broken. I’ve had an Ultegra FD R8000 series one just break.

    If the cable is not moving, start from the shifter end and make sure no frayed bits where the ferrule lug sits in the shift mechanism, then consider replacing the wire. Some are good stainless but there are plenty of shift wires that are just galvanised and over time they do oxidise and swell a bit in the housing and cause stickiness in shifting.

    Open One+ BMC TE29 Seven 622SL On One Scandal Cervelo RS
  • Wheelspinner
    Wheelspinner Posts: 6,711

    Oh, also check the bottom bracket cable guide if there is one (external cable routing). That often gets full of crud nd jams shifters too.

    Open One+ BMC TE29 Seven 622SL On One Scandal Cervelo RS
  • trevor.hall12
    trevor.hall12 Posts: 493
    edited September 7

    What make Derailler is it ?shimano stuff won't let you just pull the cable now, you need to Undo the cable tension bolt etc .

  • mark8191
    mark8191 Posts: 78
    https://forum.bikeradar.com/discussion/comment/21095242#Comment_21095242

    I managed to get the FD to shift by adjusting limit screws. However, although the bike shifts fine in the stand it struggles to make the shift when riding.

    Thoughts appreciated

  • N0bodyOfTheGoat
    N0bodyOfTheGoat Posts: 6,063
    edited September 8

    Could try loosening front mech cable clamp, push and hold front mech a bit over, pull cable through and re-tightening cable clamp.

    ================
    2020 Voodoo Marasa
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo
  • photonic69
    photonic69 Posts: 2,930

    Search for make and model of derailleur and download setup guide. Follow it to the letter. Fine tweaking might be required. Maybe worth slipping a new inner cable in to start.


    Sometimes. Maybe. Possibly.

  • trevor.hall12
    trevor.hall12 Posts: 493

    Garenteed it's a new shimano one and he's not doing anything to set it up properly.

    As soon as you take the cable odd you need to start again in the set up process

  • alanwoodison0jCj3mGl
    alanwoodison0jCj3mGl Posts: 2

    Check that the cable follows the correct approach to the derailleur bolt, either clockwise or anti-clockwise depending on the instructions for that particular model. The right route will lift the chain up to the big ring and the wrong route will struggle to do so but appear to be working satisfactorily otherwise.

  • mark8191
    mark8191 Posts: 78
    edited September 11


  • mark8191
    mark8191 Posts: 78
    edited September 11
    https://forum.bikeradar.com/discussion/comment/21095565#Comment_21095565

    SOLVED

    Looked at Shimano GRX manual. Took everything back to starting point but used the limit screw to push mech in line with outer chain ring as per the manual then, attached cable. I think it was this missing step that gave me enough tension in the cable to make the shift. Followed the rest of manual and now shifts great when riding.

    Thank you all for comments

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