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sora STI shifters question

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  1. algo
    Member

    Hello,

    I have just finished building my touring bike which I am very pleased with in general, but I am reusing old sora STI 3x9 shifters (3400) and wanted to make sure the behaviour is as it should be.

    The triple lever clicks twice to go down from the largest sprocket to the middle, and once to go down from the middle to the smallest sprocket - so there are in effect 4 positions. Is this how it should be? It is working like this, but I don't always have the smoothest transitions going to a smaller sprocket.

    As always any advice or experience much appreciated - I have tried to look elsewhere for the answer to this but most of the question that seem to be pertinent are about compatibility between triple and double.

    thanks a lot

    Posted 10 years ago #

  2. Cyclingmollie
    Member

    I think the extra click is for trimming. The slot through which the chain moves in the front mech is too narrow to allow both extremes of chain line without rubbing so the shifter has an extra movement to "trim" the mech (move it outwards slightly) to allow the chain to freely run on the highest gear.

    Posted 10 years ago #

  3. algo
    Member

    thanks for that explanation! That makes sense...

    Posted 10 years ago #

  4. kaputnik
    Moderator

    What CM said is correct. The Shimano triples seem to have 2 slightly different positions for the middle ring, to allow for using it at either the higher or lower extremes of the cassette. The Tiagra triple I have on my tourer has this feature too.

    Posted 10 years ago #

  5. algo
    Member

    hmmm - from what CM said I had understood the "trim" to apply to the largest sprocket - where the front mech is thinnest. Certainly I can edge it a bit wider once it's clicked up.

    In any case it seems it's not broken and is behaving more or less correctly - thanks a lot for the help.

    Posted 10 years ago #

  6. kaputnik
    Moderator

    @Algo it sounds like there's a subtle difference between how the Tiagra and Sora work. But it sounds like it's working as intended!

    Posted 10 years ago #

  7. algo
    Member

    @kaputnik - thanks I think you're right. To put it in context, I bought a cheap fairly knackered second hand touring bike. When I stripped it down I decided the shifters were probably ok to keep (along with almost nothing else), then I got a bit worried that perhaps they were also knackered but they seem to be ok from what you and CM say, so I have no excuse to buy any more shiny new things...

    Posted 10 years ago #

  8. Cyclingmollie
    Member

    algo: "I have no excuse to buy any more shiny new things..."

    There is always an excuse to buy shiny new things :)

    Posted 10 years ago #

  9. algo
    Member

    There is always an excuse to buy shiny new things :)

    thanks - I agree. Just got to decide which fund to raid - children don't really *need* shoes do they?

    Posted 10 years ago #

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