Changing a double to a triple chainring

Discussion in 'Cycling Equipment' started by James Lodberg, Aug 22, 2003.

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  1. > Was RE:Convert 105 STI double to triple?
    > I'm planning on getting a triple crank for my road/touring bike. Is it possible to upgrade my
    > double/8-spd 105 STI levers to work with the triple, without having to replace the whole lever?

    Howdy again,

    Sorry folks, I missed the thread from earlier this year! Let me elaborate on my situation, see
    comments below:

    > "Fred" <[email protected]> wrote in message
    > news:[email protected]...
    > > I have a Raleigh R700 with double 105 chain ring. I recently moved to the mountains and
    > > desperately need a triple crank (ok, I am a wimp). Can I easily change out the crank/chain rings
    > > but use the same front derailer?
    > >
    > > Thanks
    > Lots of ppl have done this.
    > You'll need a triple FDR, a long cage RDR, a triple crankset, and a longer bottom bracket (the one
    > recommended for the crankset).

    I have all this - the bike actually used to be my triple/8-spd XC mountain bike, now converted to a
    road & touring machine. I still use the long-cage rear derailleur, and triple front derailleur
    together with newly acquired, albeit used, drop bars & 105 STI levers. The crank is a TA Zephyr with
    the granny ring removed. This setup works great - no compatibility or shifting problems at all. I
    also have a spare bottom bracket with a 2.5mm longer axle, and a small chainring, both of which
    gather dust til the day I get a triple shifter.

    > You MAY need a new left shifter

    That's what I'm trying to avoid, due to cost...

    > Shimano shifters (Tiagra and up - Shimano 105 ST-55XX) are double/triple compatible - older
    > Shimano stuff is double (Shimano 105 ST-1055)or triple (Shimano 105 ST-1055-T) only

    ...and the fact that I can't buy a new one anyway (I have the old ST-1055, and would like to stay
    with them for now)

    > check the Shimano Europe site - or here -
    > for older stuff.

    Great link - thanks! I'm hoping to be able to simply replace the ratchet unit in the left shifter
    with the ratchet from the triple version (see link to image, below).

    Or is there more to it than this?

    > Changing the cassette to something with larger sprockets is an alternative, and cheaper,
    > option, but you will end up with larger steps between the sprockets - this may or may not be
    > acceptable to you.

    Good advice, but it's not for me. Part of the MTB-road conversion involved ditching the MTB cassette
    in favour of a nice close-ratio 12-23T road cassette. (I love to spin!)

    Cheers, James

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