Tiagra triple STI on a double crank

Discussion in 'Cycling Equipment' started by Ray1966, Oct 22, 2012.

  1. Ray1966

    Ray1966 Member

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    Hello fellow cyclists.

    I have a question that I got asked a couple of days ago by a person I was riding a charity ride with. It is about using a triple STI Tiagra ( 2011 or 2010 model shifter I think is what he said, could be older ) on a compact double. I wasn't sure, but I told him I believe it would work. My question is: If it does or will work what is the best setup?

    1) Set the shifter to the small ( Granny Ring ) position so it does the inner chain ring on a double, and the middle click would be your outer ring? ( FD stop would keep the shifter from the third outer click )

    OR

    2) On the shifter use the middle ring position for the small 34T ring , and the outer ring position for the 50T

    On number 2 option if you shifted to the granny position it would just result in allot of cable slop.

    Just wondering so you don't damage the shifter.

    The reason I would like to know, is he told me he found a good road bike at a yard sale that has the double chain rings and double FD and RD.

    The left shifter is broke. He has a good working left Triple shifter in his garage in his box of parts. He wanted to know if it would work. I told him I would ask around and let him know. He's an older rider and doesn't want to purchase a new set of shifters.

    Any help, would be helpful
     
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  2. alfeng

    alfeng Well-Known Member

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    Yes, you can use a shifter which is capable of handling three chainrings with a crankset which has only two chainrings.

    Install the Double crankset (or, remove the Granny) ...

    Set the front derailleur's stops ...

    Attach the cable as you normally would with the 'null' position being when the derailleur cage is over the inner chainring ...

    • okay, I 'know' that SunTour made at least one reverse-pull front derailleur ... but, that probably isn't an issue ...

    Tweak the front derailleur's stops, if necessary ...

    Adjust the front derailleur cable's tension, if necessary.

    Done.
     
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