Rear derailleur losing tension

reefer110
reefer110 Posts: 19
edited April 2016 in Workshop
Bloody irritating this one, despite careful adjustment my rear derailleur keeps losing tension. Every few miles I ave to play with the barrel adjustment to set it again.

Just got back from a 20 mile ride, had another fiddle and wound the barrel out so much it came unscrewed before the gears would set and 'go in properly'. Ended up having to the whole thing from scratch.

Any ideas? Bike is only 2-3 weeks old, Sora groupset, if that helps with diagnosis.

Cheers,

Comments

  • davem399
    davem399 Posts: 269
    I wonder whether the cable needs to be tightened where it is clamped on the rear mech? Sounds if it might be slipping through the clamping screw.
  • reefer110
    reefer110 Posts: 19
    I checked that, can't see that its slipping.
  • crankycrank
    crankycrank Posts: 1,830
    First thing you should do is take it back to the place you bought it from and let them sort it out before they can blame you for buggering something up. If that's not an option check to make sure the cable isn't frayed and be sure to check where it connects to the shift lever. Also could be that the cable housing wasn't butted up against the shifter body under the bar tape and is slowly creeping it's way there.
  • svetty
    svetty Posts: 1,904
    crankycrank wrote:
    First thing you should do is take it back to the place you bought it from and let them sort it out before they can blame you for buggering something up. If that's not an option check to make sure the cable isn't frayed and be sure to check where it connects to the shift lever. Also could be that the cable housing wasn't butted up against the shifter body under the bar tape and is slowly creeping it's way there.

    Agreed sounds like cable sticking somewhere as if frayed. Strange as bike is so new unless it has a kink somewhere?
    FFS! Harden up and grow a pair :D
  • jgsi
    jgsi Posts: 5,062
    Let the shop sort it... but for future reference.. a new cable can seem to take a rather long time to get the stretch out of it.
    It may take quite a few times to set the mech up and then do some test gear changes whilst on the workstand.. the cable goes slack , you need to set up again.,. repeat.. slacks then eventually it stays with the correct tension.
    If you are trying to do this work without a workstand by the way, you are making a rod for your own back.

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