Swapping my compact chainset for a triple

Special K
Special K Posts: 449
edited January 2008 in Workshop
I am currently riding Campag Veloce 10s drivetrain with a Compact chainset and 12-27 on my fast touring bike which by necessity I was also using as my "best" bike.

On tour last year with just one pannier, I found I ran out of gears on the climbs. In the coming year I want to take camping kit and cross the Alps. I fear I need more ratios. I am heavy so I know I need more...

Does anyone have any advice about converting to and riding 10s triple. I guess "keep the chain straight" is more relevant than ever right?

I guess I need to get myself an entire triple chainset and a new BB as it seems from the research I have done online today, that triples don't work with external bearing BBs which is what I currently have.

Any sage advice or pointers much appreciated.
"There are holes in the sky,
Where the rain gets in.
But they're ever so small
That's why rain is thin. " Spike Milligan

Comments

  • jpembroke
    jpembroke Posts: 2,569
    You will need a new BB. The new campag triple chainset still use an square taper BB (115.5mm) but these are very cheap (about a tenner). You won't have to change your Ergos as they are compatible with both double and triple drivetrains. You will however need a new front mech.
    I'm only concerned with looking concerned
  • simbil1
    simbil1 Posts: 620
    Maybe you could get some bigger sprockets on the back (say up to 30 or even 32T) and then change to a long cage rear mech? There was a recent thread discussing custom sprockets if your interested.
    http://picasaweb.google.com/thefirstsimbil/Bikes
  • Special K
    Special K Posts: 449
    simbil1 wrote:
    Maybe you could get some bigger sprockets on the back (say up to 30 or even 32T) and then change to a long cage rear mech? There was a recent thread discussing custom sprockets if your interested.

    got the long cage already.

    maybe I could get a custom sprocket with an escape gear of 32T. However, Ii'm happy with the gaps and the range of the cassette and I've always thought that on tooth on the chain rings up front translates to three at the back.
    "There are holes in the sky,
    Where the rain gets in.
    But they're ever so small
    That's why rain is thin. " Spike Milligan
  • Meredydd
    Meredydd Posts: 496
    I've got Veloce triple on my current bike, and have just picked up a cheap Record triple for an intended future build. As I understand it that'll require me also acquiring a suitable bottom bracket (111m Record or Chorus) and front mech. Got a set of 2006 Ergos to go with it too, which I believe will be fine. Rear mech there are, I believe, long, mid and short cage versions, but my current bike, so far as I can tell, is built with a standard Veloce short cage mech and has never given me any problems, so maybe that's not so much of an issue.
  • simbil1
    simbil1 Posts: 620
    Special K wrote:
    simbil1 wrote:
    Maybe you could get some bigger sprockets on the back (say up to 30 or even 32T) and then change to a long cage rear mech? There was a recent thread discussing custom sprockets if your interested.

    got the long cage already.

    maybe I could get a custom sprocket with an escape gear of 32T. However, Ii'm happy with the gaps and the range of the cassette and I've always thought that on tooth on the chain rings up front translates to three at the back.

    Take a look at Sheldon's site for how gear ratios work out - there's a fair bit to it and it goes beyond any simple rule. A 32T on the back should get you up anything - you could just use your bike like a 9 speed with an escape gear, not ideal but relatively easy to setup.

    http://www.sheldonbrown.com/gears/

    Sheldon also discusses how many T difference (front and back) that a rear mech can handle comfortably.
    http://picasaweb.google.com/thefirstsimbil/Bikes
  • tatanab
    tatanab Posts: 1,283
    simbil1 wrote:
    A 32T on the back should get you up anything - you could just use your bike like a 9 speed with an escape gear, not ideal but relatively easy to setup.
    There is a problem with a bail out gear. Once you are in it the jump to the next up is too big to be able to change without a considerable increase in pace.

    A few years ago in the Pyrenees I had a bottom gear of 25" with the next up at 32". A 7" difference. At the high gear end of the gear range, say 85", a jump of 7" to 92" is fine but at the low end it is not. The percentage change is simply too great to handle. What happens is you get into the lower gear, the gradient eases just a bit and you want to change up but cannot.

    You won't find my touring bike set up with big gaps. That is the advantage of modern systems with so many gears, you can have nicely judged gaps between all the gears. The lowest gear on my touring bike is 24 front 30 rear and I use an old Campag Racing Triple mech.

    A nice thing about the Campag triples is that the PCD of the inner ring is the same as for a MTB, so you can ditch the 30 and go even lower. On my best machine I have a Record triple with 50/40/24.
  • Special K
    Special K Posts: 449
    Thanks for all comments and suggestions so far.

    I think my ideal drivetrain for touring (without having to buy loads more new stuff) involves the following

    Keep the following stuff:
    Campag 10s chain
    12-27 veloce cassette
    Long cage veloce rear mech

    buy and fit new stuff:
    Front Mech Campag Racing Triple
    Crankset Campag Racing Triple
    Veloce BB solid axle

    replace the 30T on the new crankset with a 24T as per Tatanab's suggestion.

    Another alternative discussed at some length at the pub yesterday was to go 9 speed Shimano XT throughout and save the the Campag for an unadulterated proper sunday best bike (to be built this year). At least I am more familiar with Shimano XT from mountain biking and I might be slightly less nervous about bendy/broken chains.

    another question: Are Shimano Tiagra shifters compatible with XT? I could reuse some from an older bike?
    "There are holes in the sky,
    Where the rain gets in.
    But they're ever so small
    That's why rain is thin. " Spike Milligan
  • Meredydd
    Meredydd Posts: 496
    If you have a look at GB Cycles they're selling 2006 Record Triples for £80 at the moment.
  • tenor
    tenor Posts: 278
    Tatanab's suggestion is good. I also have recently fitted a Recoed triple with 50/40/30 rings. as it allows a smaller inner to be fotted - 28 in my case. I can use this with a 12/25 for lightly loaded riding and the 13/29 for heavier trips. Most people overgear their bikes and I find that 50-13 is plenty high enough when carrying any load. In fact, pretty much high enough for anything except my ego, these days!
    I didn't think that Campag did a 12/27 (?)
    A compact with a waide ratio cassette is a very poor substitute for a triple as the ratio gaps are just too big. With a bit of use you might get to prefer the triple over the compact for general riding, also. The trick is not to regard the inner ring as a last resort - changing into it early allow the use of the close ratio middle sprockets, rather than hang on the middle ring and the wider spaced inner sprockets.
    Enjoy the ride!
  • tenor
    tenor Posts: 278
    Tatanab's suggestion is good. I also have recently fitted a Recoed triple with 50/40/30 rings. as it allows a smaller inner to be fotted - 28 in my case. I can use this with a 12/25 for lightly loaded riding and the 13/29 for heavier trips. Most people overgear their bikes and I find that 50-13 is plenty high enough when carrying any load. In fact, pretty much high enough for anything except my ego, these days!
    I didn't think that Campag did a 12/27 (?)
    A compact with a waide ratio cassette is a very poor substitute for a triple as the ratio gaps are just too big. With a bit of use you might get to prefer the triple over the compact for general riding, also. The trick is not to regard the inner ring as a last resort - changing into it early allow the use of the close ratio middle sprockets, rather than hang on the middle ring and the wider spaced inner sprockets.
    Enjoy the ride!
  • Special K
    Special K Posts: 449
    tenor wrote:
    Tatanab's suggestion is good. I also have recently fitted a Recoed triple with 50/40/30 rings. as it allows a smaller inner to be fotted - 28 in my case. I can use this with a 12/25 for lightly loaded riding and the 13/29 for heavier trips. Most people overgear their bikes and I find that 50-13 is plenty high enough when carrying any load. In fact, pretty much high enough for anything except my ego, these days!
    I didn't think that Campag did a 12/27 (?)
    A compact with a waide ratio cassette is a very poor substitute for a triple as the ratio gaps are just too big. With a bit of use you might get to prefer the triple over the compact for general riding, also. The trick is not to regard the inner ring as a last resort - changing into it early allow the use of the close ratio middle sprockets, rather than hang on the middle ring and the wider spaced inner sprockets.
    Enjoy the ride!

    thank you!

    I think the cassette is probably either 12-25 or 13-29. Can't remember.
    "There are holes in the sky,
    Where the rain gets in.
    But they're ever so small
    That's why rain is thin. " Spike Milligan
  • geoff_ss
    geoff_ss Posts: 1,201
    If you don't want to fit a triple you could still use a double with (say) a 42t big ring and as small an inner ring as will fit on you crank. 42x12 is higher than 90" and more than enough when cycle camping. The low gears are far more important than the high for laden touring in mountains. So just shift the whole lot down if it's easier and keep them close.

    IIRC correctly I used a 48/36 double with a 6 speed 13/28 block for cycle camping in the Pyrenees and rarely used bottom gear, even over the Tourmalet. Of course I was 20 years years younger then and a mere stripling in my 40s :lol:

    Geoff
    Old cyclists never die; they just fit smaller chainrings ... and pedal faster

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