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  1. #1
    Senior Member Briareos's Avatar
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    Should Road-Conversions Utilize Road Cranks?

    I have been building up a 130mm rear spacing road bike for fixed-gear, and was simply planning on getting an IRO drivetrain to start with. But I forgot to consider chainline and things like that and now I'm not so sure about my choice. Chain-line and BB size are things I have trouble understanding, I can't visualize it in my head so it's difficult.

    With 130mm rear-spacing, what sort of things should I be thinking about? Should I use road cranks with one chainring to achieve a better chainline? I've read some threads using the search function but like I said, it's mind-bending. The BB is a standard 68mm English thread (It's a GT Strike road bike).

    Anyone have any ideas on how I can get a nice balance of chainline with either track or road parts?

  2. #2
    LF for the accentdeprived
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    What hub do you want to use? Flipflop or not?
    Chances are that it will have a 42 mm chainline. See if your chainstay allows you to go 42mm with the chainring you want. If it does, go 42 for simplicity. Track bb and track crank.
    However, getting a road crank and a shortish bb will prolly be cheaper. 45ish chainline, which is a bit trickier to match with your hub.
    Quote Originally Posted by dutret
    Do you deny that you are clueless or do you just think that "moron" didn't need to be tacked on there?
    Bike on flickr and on FGG

  3. #3
    Senior Member
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    Sometimes a track crank will hit the chainstay on road frames with a short BB.

  4. #4
    Crazy-assed messanger
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    There's aways flipping the bracket over so the left side (shorter) is on the right...that often works, though it's often easier if you have an old-school spindle bracket and a box full of other ones to try.

    Trial and error are integral parts of bike mechanics.

  5. #5
    LF for the accentdeprived
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    Quote Originally Posted by thurstonboise
    Sometimes a track crank will hit the chainstay on road frames with a short BB.
    Hence:"See if your chainstay allows you to go 42mm with the chainring you want"
    Quote Originally Posted by dutret
    Do you deny that you are clueless or do you just think that "moron" didn't need to be tacked on there?
    Bike on flickr and on FGG

  6. #6
    Senior Member mihlbach's Avatar
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    what road crank do you plan on using? There are online databases for cranks and chainline. That should help you deterine what BB will give you a 42mm chainline.

  7. #7
    Senior Member Briareos's Avatar
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    Quote Originally Posted by mihlbach
    what road crank do you plan on using? There are online databases for cranks and chainline. That should help you deterine what BB will give you a 42mm chainline.
    Well, I can use a set of C-Record cranks a friend has no use of, and neither of us knows what BB length they use and what parts to use with it.

    The other option is a Centaur Ultra-Torque crankset (one-ring obviously). I hear the difference between those cranks and regular ones is quite noticeable and I'd like to try it with a fixed gear or singlespeed.

    If those two options turn out to be too much of a hassle, I'll probably get an IRO drivetrain.

  8. #8
    o.O Seggybop's Avatar
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    It's a lot easier to mess with spacers on your chainring bolts than to switch out the crank or BB, so try that first.
    mi yu mi yu

  9. #9
    mmm bikes
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    The bottom bracket will probably be quite low so you want to go for 165 mm long to avoid pedal strike in corners. Not sure but you may have better luck finding that length with track gear? most road cranks are 170-175. Not sure what is available to you.

    I have 165's on my road conversion and no worries until I tried racing, which was very scary in the bends!

    I think Sheldon Brown has some measurements regarding sprockets, rings, and chainline. I just ordered my stuff and was lucky.

  10. #10
    Paste Taster Retem's Avatar
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    save yourself some money and just get a shorter bb
    I am dyslexic so bear with my posts.... [SIGPIC][/SIGPIC]

  11. #11
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    IMO, road cranks are far superior to track cranks in every way.

  12. #12
    Gone, but not forgotten Sheldon Brown's Avatar
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    Quote Originally Posted by BostonFixed
    IMO, road cranks are far superior to track cranks in every way.
    Could you be more specific?

    How many ways are there for a crank to be "superior?" They're not lighter, they're not stiffer, they're not stronger... May be prettier...

    They also commonly use the semi-obsolete 144 mm bolt circle, for which chainring selection is rather poor and the rings available tend to be unreasonably expensive due to their rarity.

    Sheldon "Cranks Don't Really Know Where They're Being Ridden" Brown
    [COLOR=blue][CENTER][b]Harris Cyclery, West Newton, Massachusetts[/b]
    Phone 617-244-9772, FAX 617-244-1041
    [URL= http://harriscyclery.com] http://harriscyclery.com[/URL]
    Hard-to-find parts shipped Worldwide
    [URL=http://captainbike.com]http://captainbike.com[/URL]
    Useful articles about bicycles and cycling
    [URL=http://sheldonbrown.com]http://sheldonbrown.com[/URL] [/CENTER] [/COLOR]

  13. #13
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    Quote Originally Posted by Sheldon Brown
    Could you be more specific?

    How many ways are there for a crank to be "superior?" They're not lighter, they're not stiffer, they're not stronger... May be prettier...

    They also commonly use the semi-obsolete 144 mm bolt circle, for which chainring selection is rather poor and the rings available tend to be unreasonably expensive due to their rarity.

    Sheldon "Cranks Don't Really Know Where They're Being Ridden" Brown
    I think you read my statement backwards.

  14. #14
    Paste Taster Retem's Avatar
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    hey wait I have old school road cranks that are 144bcd what should I do??? hehehh
    I am dyslexic so bear with my posts.... [SIGPIC][/SIGPIC]

  15. #15
    Gone, but not forgotten Sheldon Brown's Avatar
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    Quote Originally Posted by BostonFixed
    I think you read my statement backwards.
    !did I sseug I seY

    yrroS

    nodlehS
    [COLOR=blue][CENTER][b]Harris Cyclery, West Newton, Massachusetts[/b]
    Phone 617-244-9772, FAX 617-244-1041
    [URL= http://harriscyclery.com] http://harriscyclery.com[/URL]
    Hard-to-find parts shipped Worldwide
    [URL=http://captainbike.com]http://captainbike.com[/URL]
    Useful articles about bicycles and cycling
    [URL=http://sheldonbrown.com]http://sheldonbrown.com[/URL] [/CENTER] [/COLOR]

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