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Front Mech Won't Shift with New Cable

mark8191mark8191 Posts: 60
edited October 2020 in Workshop
Replacing a snapped front shifter cable but can't get the front mech to move when I shift. It's as if there isn't enough tension to move the mech but I pulled the new gear cable taught when fastening it under the plate on top of the mech.

I feel like the cable isn't sitting right in the barrel adjuster as it feels a bit flimsy.
Can someone tell me where I've gone wrong before I admit defeat please!?

Started with shifter in the smaller chainring setting
Cut new housing to same length as previous
Used tooth pick to open up the ends of new cable/ lubed openings
Passed new cable through guide under bottom bracket
Tightened new cable under plate









Posts

  • me-109me-109 Posts: 1,386
    Is the shift lever moving or not? If you unclamp the cable and just pull it with your fingers while operating the shifter, can you feel the cable move?
  • me-109 said:

    Is the shift lever moving or not? If you unclamp the cable and just pull it with your fingers while operating the shifter, can you feel the cable move?

    Yes, the shift leaver does move and will move the cable if I just hold on to it but when I attached it to the mech it just doesn't have the power to make the shift
  • me-109 said:

    Is the shift lever moving or not? If you unclamp the cable and just pull it with your fingers while operating the shifter, can you feel the cable move?

    Just tried something and found when cable is clamped the shifter struggles to make more than one click
  • wongataawongataa Posts: 921
    edited October 2020
    Download the installation instructions (dealer manual) from Shimano and follow them exactly. With this design of derailleur you need to follow the Shimano method or it won't work properly.

    Take the cable off and start from the beginning.

    They are not set up like front derailleurs used to be.
  • david37david37 Posts: 1,313
    the answer is usually related to the way the cable is routed in the final few CM at the Front Mech. have a cup of tea wander round and swear at some stuff and then try again.

  • david37 said:

    the answer is usually related to the way the cable is routed in the final few CM at the Front Mech. have a cup of tea wander round and swear at some stuff and then try again.

    Already done plenty of swearing but will do! haha
  • arlowoodarlowood Posts: 2,519
    Might help a bit if you gave it a clean because later on you will need to align some markings to get the correct tension.

    Have a look at this installation video - the guy's a bit boring on the delivery side but he covers all you need to know. You should start watching after about 4m30secs



    Worked for me when I had a shifting issue on a new bike - couldn't get the chain onto the big ring. Turned out tension was too low and I adjusted it to align the two marks as described in the video.
  • cq20cq20 Posts: 207
    Had a similar thing happen with a 105 5800 front changer. Turned out to be User error. I had clicked the lever to the lowest position before fitting the cable but had left the rubber hood folded back which had stopped the internal mechanism moving to the lowest position (aware I’m not explaining this too well!). I eventually got the cable completely back out of the levers (was difficult because it hadn’t bedded in the correct position), put the rubber hood back to its normal position, clicked the lever down to lowest setting, folded the hood back to gain access, inserted the cable again and this time everything was fine
  • wongataawongataa Posts: 921
    arlowood said:

    Might help a bit if you gave it a clean because later on you will need to align some markings to get the correct tension.

    Have a look at this installation video - the guy's a bit boring on the delivery side but he covers all you need to know. You should start watching after about 4m30secs



    Worked for me when I had a shifting issue on a new bike - couldn't get the chain onto the big ring. Turned out tension was too low and I adjusted it to align the two marks as described in the video.

    Or you just follow the freely available Shimano instructions from their website.
  • me-109me-109 Posts: 1,386
    I'm not familiar with those Shimano shifters so can't tell from pic 3 whether that cable is far enough in to be on the spool and free of the body.
  • Had same issue.
    Watched 'many' You Tube vids before I started.
    Replaced cable inner and outers and front derailler on my Shimano 105/5700 set up.
    Couldn't get chain to shift up to big ring.
    After many many attempts I finally,by good luck I think, managed to pull cable sufficiently taught before clamping and hey presto it worked.
    Pulling/clamping the cable on this final successful attempt didn't feel any different to all my previous attempts so I have no wise words..I just persevered.
    Once on the big ring I tweaked the barrel adjuster to add a bit more tension and tweaked the high set screw.
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