Changing a double to a triple chainring

Discussion in 'Cycling Equipment' started by Fred, May 10, 2003.

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  1. Fred

    Fred Guest

    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
     
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  2. Are you sitting down? To change to a triple you'll definitely need to replace the front derailleur
    and most likely the rear as well. The f. der. won't have enough throw and r. der's cage will be too
    short to take up the extra slack in the chain. Further, you'll very likely need to change your
    bottom bracket as well because the inner chainring and/or its bolt heads probably won't clear the
    chainstays. AND, if you're really unlucky, your frame won't work either because the dimple in the
    chainstay will be in the wrong position, or not long enough. (I had this problem with an older
    Waterford frame, but I was able to modify it with the help of a press.)

    Sorry, don't shoot the messenger.

    Trevor

    "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
     
  3. Josh Gatts

    Josh Gatts Guest

    > "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
    >
    >
    "Trevor Taylor" <[email protected]> wrote in message
    news:[email protected]...
    > Are you sitting down? To change to a triple you'll definitely need to replace the front derailleur
    > and most likely the rear as well. The f.
    der.
    > won't have enough throw and r. der's cage will be too short to take up the extra slack in the
    > chain. Further, you'll very likely need to change your bottom bracket as well because the inner
    > chainring and/or its bolt heads probably won't clear the chainstays. AND, if you're really
    > unlucky, your frame won't work either because the dimple in the chainstay will be in the wrong
    > position, or not long enough. (I had this problem with an older Waterford frame, but I was able to
    > modify it with the help of a press.)
    >
    > Sorry, don't shoot the messenger.
    >
    > Trevor
    >

    A cheaper option would be to put on an MTB cassette and rear derailleur. You could go as low as a
    39/34, which is pretty durn low for a road bike. Big gaps between gears can be annoying, though.

    --Josh
     
  4. fred-<< 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.

    Probably not and unless you haver downtube left shifter, you will need a new shifter as well.

    To go triple need a new BB, triple crank, front der, maybe a shifter and ideally, a long
    cage rear der.

    OR, get a shimano MTB long cage rear der, then you can get a MTB casette with as big as a 34t big
    cog, and keep the double ring. Cheapest solution.

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"
     
  5. Grenouil

    Grenouil Guest

    "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). You MAY need a new left shifter - newer 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 - check the Shimano Europe site -
    http://www.shimano-europe.com/cycling/index.phtml or here -
    http://www.fa-technik.adfc.de/Hersteller/Shimano/DIGEST.html for older stuff.

    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.
     
  6. A Muzi

    A Muzi Guest

    > "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?

    "Trevor Taylor" <[email protected]> wrote in message
    news:[email protected]...
    > Are you sitting down? To change to a triple you'll definitely need to replace the front derailleur
    > and most likely the rear as well. The f.
    der.
    > won't have enough throw and r. der's cage will be too short to take up the extra slack in the
    > chain. Further, you'll very likely need to change your bottom bracket as well because the inner
    > chainring and/or its bolt heads probably won't clear the chainstays. AND, if you're really
    > unlucky, your frame won't work either because the dimple in the chainstay will be in the wrong
    > position, or not long enough. (I had this problem with an older Waterford frame, but I was able to
    > modify it with the help of a press.)
    >
    > Sorry, don't shoot the messenger.

    Nice overview but the problem with the front changer isn't the range of lateral movement, just the
    depth of the cage. And the chainstay clearance can be measured before selecting a crank bearing
    assembly - should not be a surprise.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  7. Garyg

    Garyg Guest

    "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

    Sheesh...ignore all that advice about upgrading components.

    Assuming you're not single, tell your significant other that those mountains require a new bike.

    GG
     
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