One click or Two (Road Bike Front Mech)

Discussion in 'Bicycle Mechanics and Repairs' started by mondobongo, 8 Sep 2007.

  1. mondobongo

    mondobongo Über Member

    Changing down on my front mech I have found it requires two clicks of the Tiagra STI lever to drop down is this normal? Or is the front mech set up wrong when it changes it is slick and not at all clumsy my limited knowledge of road bikes says is this to prevent accidental down shifts. Am used to MTB shifting which was one click up or down.
  2. TheDoctor

    TheDoctor Resistance is futile! Moderator

    Is the first click a trim for the front mech to stop the chain rubbing on the big ring / big cog gears?
  3. alecstilleyedye

    alecstilleyedye nothing in moderation Moderator

    double or triple? never had that problem on my triple tiagra. are you using a three speed (left) shifter with a double chainset?
  4. OP

    mondobongo Über Member

    Its a triple.
  5. gavintc

    gavintc Guru

    I have a similar groupset on my winter bike. The middle cog/chainring has a trim setting. I find if I am in the lower or upper 4 gears, I need to trim the front derailleur by making a small 1/2 change to the left or right. This prevents the chain rubbing on the plate. If I then change down to the lower range, sometimes I need to click twice to get the derailleur to move completely across to the small chainring.
  6. gkerr4

    gkerr4 New Member

    two clicks sounds fine - there are actually 4 positions on the triple mech - innermost, outermost and two positions for the middle chainring - so it can be 'trimmed' not to rub on the mech depending on what cassette sprocket you are in.

    the double has three positions - for the same reason
  7. OP

    mondobongo Über Member

    Thanks for the replies.

    Have now had the chance to give it a good once over the movement in the mech on the first click is very small with a larger movement to shift the chain down coming on the second click. Which ties in with the trimming suggested.

    Had initially discounted trimming as when I read up on this on Sheldon he gave the opinion that modern mechs do away with the need to trim. On ride last night paid really close attention to gear noise and a little trim alleviated any that cropped up. You live and learn.
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