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How to convert Compact to Tripe?

mikehiggsmikehiggs Posts: 12
edited September 2010 in Workshop
Hi,

sorry if this is a repeat, couldn't find a post.

I have a compact with two front rings and may want to convert to a triple. I imagine it must be possible but am not sure how much of what's there I need to replace. I think I'd need a new crank with three rings instead of two and assume I need to change the front derailleur and possibly lever too?

Any help appreciated.

Thanks

Posts

  • sungodsungod Posts: 16,060
    yes, you'd need to change the cranket, the front mech and the shifter

    won't be cheap, but you could keep an eye on ebay etc. for bits, it's the shifter and crankset that will cost you

    if you are doing it to get a lower gear, might be worth considering a cassete with bigger max cog, depends what you've got now though, if you already have a xx-26 or bigger then there's not much room for more
    my bike - faster than god's and twice as shiny
  • Monty DogMonty Dog Posts: 20,614
    If you have an external BB chainset - you can't because there's no room inboard of the middle ring to fit a third ring plus no way of lengthening the axle. If you have an older chainset with a seperate BB. You may be able to find a 'mountain tamer' chainring adaptor - now obsolete so ebay only that allows you to bolt an extra ring to the inside of your middle one and fit a longer bottom bracket to compensate. You'll also need at least a new front mech, probably a long/medium cage rear mech and possibly shifters! Maybe not such a good idea after-all?
    Make mine an Italian, with Campagnolo on the side..
  • sungodsungod Posts: 16,060
    Monty Dog wrote:
    If you have an external BB chainset - you can't because there's no room inboard of the middle ring to fit a third ring plus no way of lengthening the axle. If you have an older chainset with a seperate BB. You may be able to find a 'mountain tamer' chainring adaptor - now obsolete so ebay only that allows you to bolt an extra ring to the inside of your middle one and fit a longer bottom bracket to compensate. You'll also need at least a new front mech, probably a long/medium cage rear mech and possibly shifters! Maybe not such a good idea after-all?

    eh?

    the op isn't talking about bodging an extra ring on, he clearly says he will "need a new crank with three rings instead of two"

    if i've got, say, a 105 56xx series, which is external bb, i can fit a double or a triple crankset, absolutely no issue

    the axle is part of the crankset, no need to 'lengthen the axle, the triple fits on exactly the same bb as a double, just adds a spacer so that the left crank is at the same distance out as the right
    my bike - faster than god's and twice as shiny
  • fixiebobfixiebob Posts: 222
    If ypu have older internal bb you will have to change it too one for triple is slightly longer I believe and any triple's I hae seen have longer cage rear mech's seem's like a lot of money I'd do hill rep's and keep your compact I am running a 50 - 34 with 12 - 27 at the back giving an easy gear of 34 -27 should be able to ride up a lampost on that :)
  • Berk BonebonceBerk Bonebonce Posts: 1,245
    You will def need a new chainset, BB and front mech.

    You might also need a new front shifter and rear mech.

    What's the problem with the gears you got at the moment? Changing chainrings might be a better option for you.
  • mikehiggsmikehiggs Posts: 12
    Thanks for the replies.

    It's 105 gearing with an external BB (looks like the Hollow Tech I have on the mtb?).

    The main problem with what I have now is my legs :roll: To be honest, I've only ridden the thing a couple of times and when on steeper climbs it crossed my mind a smaller front ring mght be nice. I suppose though with training and practice etc, I might well get by without.

    I'll check what my ratios are.

    Cheers
  • father_jackfather_jack Posts: 3,509
    Somehow I don't think the intestines of a animal would make a good chainset. :wink:
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • mikehiggsmikehiggs Posts: 12
    Don't get the intestines one ... :?:

    Just checked and mine has 50/34 on the front and 12-27 on the back. The equivalent triple has 50/30 on the front which is a difference of 1.25 against 1.1 so I think the training and hill work are the first things to try. Sigh...

    Thanks again
  • protoproto Posts: 1,483
    Lot of hassle. Personally, I wouldn't have the stomach for it. :)
  • bicebice Posts: 772
    It's a smart move and will give you a smoother bike. 50/34 was the vilest combination I have attempted. Hated the massive chainring leap. Hated the savage chain line.

    My triple is far more versatile, and so is my standard double. Compacts are neither fish nor fowl.

    I changed the 34 for a 40, which was an improvement in London. Then left the bike in Wales, where I need the 34 ... which would mean never getting a decent gear on the flat again.
  • father_jackfather_jack Posts: 3,509
    proto wrote:
    Lot of hassle. Personally, I wouldn't have the stomach for it. :)

    Does it take a lot of guts to change a chainset? :wink:
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • mikehiggsmikehiggs Posts: 12
    OK< I'm catching up with my intestine typo now!

    :D
  • mikehiggsmikehiggs Posts: 12
    bice wrote:
    It's a smart move and will give you a smoother bike. 50/34 was the vilest combination I have attempted. Hated the massive chainring leap. Hated the savage chain line.

    So which bits did you have to replace?

    Thanks
  • bicebice Posts: 772
    Crankset, chain, possibly front mech, possibly BB. I would get second hand parts as people sell off triple stuff to opt for double or compacts.

    I haven't changed my compact over to a triple; I have three road bikes.
  • father_jackfather_jack Posts: 3,509
    I haven't changed my compact over to a triple; I have three road bikes.

    I have two bikes both triples, I have not changed them to doubles either.
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
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