Smallest Road Triple Chainrings

Discussion in 'Cycling Equipment' started by ator539, Jul 15, 2007.

  1. ator539

    ator539 New Member

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    I am interested in having a touring bike with very, very low gearing for loaded touring on paved roads in hard mountains. I'd like to go with a touring-specific bike, for the drop bars, integrated shifters (STI), and geometry, but I need to put something like mountain gearing on it. Many touring specific bikes come with chainrings around 30/40/50. I'd like to have 22/32/44. I have two questions: (A) Can I just put a mountain bike crankset on a road-style bike, so long as I can lower the clamp on the front der., and use my STI? (B) Barring that, what is the smallest chainring set I can swap out on a road triple--will it depend on bolt diameter, etc.? Basically, I am looking for suggestions to get very, very low gearing on a road-style touring bike. Lastly, the Rohloff internal gear hub would easily put me in my desirable gear range, but it would put me very far out of my desireable bank account range, so I'm looking for other options.
    Thanks for your time.
     
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  2. xxamr_corpxx

    xxamr_corpxx New Member

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    Have you considered changing the rear cassette? Shimano make a 14-34 cassette that should be low enough for almost everything. You may have to change your RD as well, but something like a Sora long cage will be pretty cheap.
     
  3. Retro Grouch

    Retro Grouch New Member

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    The issue is the STI shifters.

    If you use a mountain bike crankset, you would be well advised to also use a mountain bike front derailleur because it will match the smaller chainrings much better. Unfortunately, while I've never tried it personally, I'm told that STI shifters don't mate very well with mountain bike front derailleurs.

    You can solve this problem by using barcon shifters. For a loaded touring bike that has the added advantage of replacing a complicated and expensive component with one that's much simpler, cheaper, and more reliable.
     
  4. Retro Grouch

    Retro Grouch New Member

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    A Sora long cage won't do it. The upper pulley will rub the big cog. Fortunately, a mountain bike derailleur will both handle the 34t cog and index with the STI shifters.
     
  5. ator539

    ator539 New Member

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    Thanks for the suggestion. But, I'm looking for an extra-small crankset compatible with STI. The touring bikes I am looking at all come with fairly large rear cassettes. It is just the front that worries me. I'm definitely no pro, and will need all of the gearing I can get. Also, I have a chronic knee issue/pain if I get below 80 cadence. So I'm looking for as small a crank as I can get, even with the cassette you mention.

     
  6. ator539

    ator539 New Member

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    Thanks, I was thinking about building up a bike using a MTB crankset with road shifters and derailleurs. I thought it was odd that no one seems to do it, but I guess there is a reason.



     
  7. gclark8

    gclark8 New Member

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    Most of us want to go faster not slower. ;)

    I have fitted MTB cranksets to small bikes, 160mm arms with 28/38/48 chainrings.
    I use the BB length recomeded by the crank manufacturer and a
    Shimano Front Derailleur,
    FD-CO50 for 44/46 tooth,
    FD-CO51 for 48 tooth,
    FD-R443A for 52/53 tooth.
    These have worked OK for me with 8 speed road shifters.

    This topic may help: http://www.cyclingforums.com/t363004.html
     
  8. geoffs

    geoffs New Member

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    Not sure about how well STI lever will work with the front derailleur but I would be suprised if it were a problem. I would be using a n-gear chain watcher to avoid dropping the chain though. The rear STI with a XT or XTR works fine as both of my tandems have this arrangement.
    What are you going to do for brakes though? To use STI levers on V-brakes you will need to install a travel-agent to change the amount of cable pull. Alternatively you could use Tektro mini V's.

    Cheers

    Geoff
     
  9. WIGGUM1

    WIGGUM1 New Member

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    I have an uncle that has ridden across the country several times. He is avid old school and doesnt like new technology. He wanted a smaller ring in front and ended up having one custom cut. You might want to look into that.
     
  10. artemidorus

    artemidorus New Member

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    No problemo. You need a Shimano MTB front derailleur, a Shimano MTB crankset, a matched Shimano BB and a Campagnolo Ergopower left shifter. The Campag shifter has numerous small increments of adjustment for the Shimano FD and works perfectly. Shimano STI will not work with an MTB FD - don't consider trying it. I picked up an unused '98 Veloce left shifter on ebay for $45.
    If you want to go the whole hog, a Shimano long cage MTB rear derailleur will work with a cassette with a large sprocket of up to 34T and will work with your existing Shimano STI right shifter.
     
  11. ator539

    ator539 New Member

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    I initially excluded a MTB conversion, but I'll have to reconsider, especially when price is factored in. Thanks for the tip and link to other forum.



     
  12. ator539

    ator539 New Member

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    Thanks for the suggestion, but I think that I'll be OK with the brakes. The touring bikes I am looking at have canti brakes and STI, which are supposed to go fine together. Now, I could have used your advice when I was bulding up a Surly with Nexus a few years ago (I've since had to put in travel agents).




     
  13. peter75

    peter75 New Member

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    You can do this with a Shimergo set up ie use Camapagnolo Ergo shifters with Shimano gears - its described here http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3946

    Other advanatge is that Campage kit is a lot cooler than Shimano:)
     
  14. artemidorus

    artemidorus New Member

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    You don't want the Campag right shifter. That would commit you to using Campag RD, cassette and freehub, or else botching around with travel agents and anchor bolt "B" positions.
    Shimano gear is easier to come by in isolated bike shops outside continental Europe, I would wager.
     
  15. peter75

    peter75 New Member

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    The CTC website article says you can use Camapg right lever with shimano mtb rear as does Sheldon Brown on his website.

    Appreciate the point about isolated bike shops - presumably Camapg stuff is an unknown to you Aussies!!:)
     
  16. artemidorus

    artemidorus New Member

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    Not at all - it is available in all of the most expensive shops in the cities. Goes nicely with other "bling" bits, if you want to pay for it.
    As for Campag shifter with MTB RD - I can't imagine that it would shift as nicely as a Shim/Shim match, as the two different brands of shifter pull different cable lengths per shift. To me, the crisper rear shift is worth having to have mismatching levers.
     
  17. nerdag

    nerdag New Member

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    Having used this setup now for about three months now on my commuter, I can positively attest that the Shimergo solution works brilliantly.

    The rear shifting feels just as crisp as a genuine Shimano match. IMHO, I think it feels better than the 9sp MTB shifters (although I was using *only* Deore). It has a much more solid feel to it than the Ultegra shifters on my road bike do (although I do like that the Ultegra levers feel very precise).

    I like it so much that I am thinking about turning my primary road bike into a Shimergo mongrel, since Shimano consumables are usually cheaper, but the feel of the ergopower levers is comfy in my (small) hands.

    n
     
  18. nerdag

    nerdag New Member

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    I should also add that even with all the abuse that the bike this is set up on cops on suburban roads, the shifting hasn't needed any adjusting since it was installed.

    n
     
  19. artemidorus

    artemidorus New Member

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    Does the cable anchor in the standard position on the RD?
     
  20. nerdag

    nerdag New Member

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    No it doesn't - it anchors 180deg to the Shimano B position described by Sheldon Brown.

    There's a diagram on the CTC website that shows you where to anchor it if you were wanting to give it a try.

    Looks a little something like this:
    [​IMG]

    n
     
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