Tiagra front mech

Ben1980
Ben1980 Posts: 21
edited August 2016 in Workshop
Hi everyone I've just bought a Defy Advanced 3 and I'm shocked at how poor the Tiagra front mech shifts so I'd like to fix it with an upgrade but can't stretch to a full groupset upgrade at the moment, I'm not sure which part is responsible for the poor shifting the mech, the sti or a bit of both ?

Thanks in advance :)

Comments

  • imposter2.0
    imposter2.0 Posts: 12,028
    There's no reason why Tiagra should not shift perfectly well, assuming the lever is functional, the mech is functional and the cable is moving freely.
  • Ben1980
    Ben1980 Posts: 21
    Imposter wrote:
    There's no reason why Tiagra should not shift perfectly well, assuming the lever is functional, the mech is functional and the cable is moving freely.

    It's truly shocking, I've to shift down twice to get the mech to move over fully, never had that with 105 or Ultegra.
  • Ben1980
    Ben1980 Posts: 21
    I've also played around with the barrel adjuster with no success, seems very clumsy compared to the others.
  • andy9964
    andy9964 Posts: 930
    What chainset does it have? Mine shifts much nicer since I swapped the FSA/BB30 crank for the 4700 Tiagra, much less clunky on the shift from big - small
  • homers_double
    homers_double Posts: 8,276
    When I upgraded to 105 the front mech was very stiff, it workedbut took some effort to move.

    A few rides later and it had eased off so I put it down to new springe etc knowing everything else was working freely.
    Advocate of disc brakes.
  • imposter2.0
    imposter2.0 Posts: 12,028
    Ben1980 wrote:
    Imposter wrote:
    There's no reason why Tiagra should not shift perfectly well, assuming the lever is functional, the mech is functional and the cable is moving freely.

    It's truly shocking, I've to shift down twice to get the mech to move over fully, never had that with 105 or Ultegra.

    So there's obviously a problem somewhere - but there's nothing intrinsically wrong with Tiagra which would make it perform like that.
  • Ben1980
    Ben1980 Posts: 21
    Andy9964 wrote:
    What chainset does it have? Mine shifts much nicer since I swapped the FSA/BB30 crank for the 4700 Tiagra, much less clunky on the shift from big - small

    It's got the Tiagra chainset Andy.
  • Ben1980
    Ben1980 Posts: 21
    Imposter wrote:
    Ben1980 wrote:
    Imposter wrote:
    There's no reason why Tiagra should not shift perfectly well, assuming the lever is functional, the mech is functional and the cable is moving freely.

    It's truly shocking, I've to shift down twice to get the mech to move over fully, never had that with 105 or Ultegra.

    So there's obviously a problem somewhere - but there's nothing intrinsically wrong with Tiagra which would make it perform like that.

    Yeah I'm starting to think the same, as far as I'm aware it should shift fully over in one shift then if u shift agian it will trim.
  • Ben1980
    Ben1980 Posts: 21
    homers double wrote:
    When I upgraded to 105 the front mech was very stiff, it workedbut took some effort to move.

    A few rides later and it had eased off so I put it down to new springe etc knowing everything else was working freely.

    I understand what you mean, it feels like the cable is too tight which is stopping it from shifting down but I've played with the barrel which has had no effect.
  • trailflow
    trailflow Posts: 1,311
    Which FD version of Tiagra 4600 or 4700 ?
  • Semantik
    Semantik Posts: 537
    Ben1980 wrote:
    homers double wrote:
    When I upgraded to 105 the front mech was very stiff, it workedbut took some effort to move.

    A few rides later and it had eased off so I put it down to new springe etc knowing everything else was working freely.

    I understand what you mean, it feels like the cable is too tight which is stopping it from shifting down but I've played with the barrel which has had no effect.

    Finding it hard to shift down from big ring is nearly always too much cable tension. Another symptom is usually very little movement at the front mech when trying to 'trim' on the big ring.

    You would do well to start from scratch. Maybe your barrel adjuster has run out of adjustment? In what conditions are you trying to turn the barrel adjuster? When cable is at its slackest, I.e chain on little ring or when chain is on the big ring? -makes a difference. Don't do it when chain is on the big ring as cable is already very tight. Put chain on small ring and undo the front mech cable pinch bolt and then check that the barrel adjuster turns. Turn it all the way in then pull the cable through again and retighten pinch bolt. Now check front shifting including trim function and increase cable tension with barrel adjuster if necessary.
  • keef66
    keef66 Posts: 13,123
    My old 9 speed Tiagra front mech shifts very sweetly.

    Is this the new 4700 stuff? Heard about several cases where the LH shifter went kaput when fairly new; maybe they are more demanding in terms of cable tension...?
  • Ben1980
    Ben1980 Posts: 21
    trailflow wrote:
    Which FD version of Tiagra 4600 or 4700 ?

    I believe it's 4700 trailflow
  • Ben1980
    Ben1980 Posts: 21
    Semantik wrote:
    Ben1980 wrote:
    homers double wrote:
    When I upgraded to 105 the front mech was very stiff, it workedbut took some effort to move.

    A few rides later and it had eased off so I put it down to new springe etc knowing everything else was working freely.

    I understand what you mean, it feels like the cable is too tight which is stopping it from shifting down but I've played with the barrel which has had no effect.

    Finding it hard to shift down from big ring is nearly always too much cable tension. Another symptom is usually very little movement at the front mech when trying to 'trim' on the big ring.

    You would do well to start from scratch. Maybe your barrel adjuster has run out of adjustment? In what conditions are you trying to turn the barrel adjuster? When cable is at its slackest, I.e chain on little ring or when chain is on the big ring? -makes a difference. Don't do it when chain is on the big ring as cable is already very tight. Put chain on small ring and undo the front mech cable pinch bolt and then check that the barrel adjuster turns. Turn it all the way in then pull the cable through again and retighten pinch bolt. Now check front shifting including trim function and increase cable tension with barrel adjuster if necessary.

    Thanks for the advice, I'll try this and post the results.
  • Ben1980
    Ben1980 Posts: 21
    keef66 wrote:
    My old 9 speed Tiagra front mech shifts very sweetly.

    Is this the new 4700 stuff? Heard about several cases where the LH shifter went kaput when fairly new; maybe they are more demanding in terms of cable tension...?

    Yes I believe so keef66, the front mech shifter doesn't feel like it will last long the way it's shifting at the moment.
  • trailflow
    trailflow Posts: 1,311
    Try setting up the FD again from scratch. Try this tutorial i made here viewtopic.php?t=12976309
  • Ben1980
    Ben1980 Posts: 21
    Okay cheers for the info guys it's shifting a lot better now I did a full reset as advised, turns out there was a ridiculous amount of tension in the cable which made the barrel adjuster useless which is shocking considering it's just had a PDI at the retailer, it had massive brake rub also :roll:

    Thanks again :D
  • Semantik
    Semantik Posts: 537
    Ben1980 wrote:
    Okay cheers for the info guys it's shifting a lot better now I did a full reset as advised, turns out there was a ridiculous amount of tension in the cable which made the barrel adjuster useless which is shocking considering it's just had a PDI at the retailer, it had massive brake rub also :roll:

    Thanks again :D

    Once you know what you're doing you will never trust a bike shop to do a proper job again.They will rarely do as good a job as you can do yourself.

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