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  1. #1
    Senior Member meltron's Avatar
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    A Question about Gear Ratio's

    I currently ride a singlespeed at 50x16. I have on order a fixed rearwheel and now the dilemma is what cog to get. I've got a feeling running 50x16 fixed is going to be a bit tough of a ride...or not?

    Should I get a 17t cog or go as far as getting a new chainring for a slightly lower/manageable fixed ride. One of the techs over at bikeworks nyc runs 50x17 fixed and says its not too bad.

    Cheers.

  2. #2
    McNightrider
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    Run 17 or 18T cogs, you should be set. I used to run 51x16 its tough to ride up the hill with my massive body and ****ty heart.
    Now I am running 46x16..alot better, but I am going to run 18T cog soon I will tell u what happen. hehe

  3. #3
    >< neuron's Avatar
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    i ran 52/16 SS for three months, and then 52/15 fixed for a year. i then dropped to 52/17, and then to 48/15, and am currently running 48/17 on my new bike.

    depends on if you want to push or spin.

  4. #4
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    That is a pretty high gear. If you're used to pushing it on a singlespeed it won't really be much different fixed. But you might enjoy the jump to a smaller ratio if you try it, with either an 18 tooth cog for 75" or a 19 toother for 71". I really like a 69" gear (47/18) though it's not for everyone. Small gears on a fixed are all about power and control---easier to get going, easier to slow down.
    Last edited by mander; 05-16-07 at 11:08 AM.

  5. #5
    McNightrider
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    I thought 46/18 is 69"?? That is what i wanna achieve.

  6. #6
    Senior Member 1fluffhead's Avatar
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    Quote Originally Posted by vee_dub
    I thought 46/18 is 69"?? That is what i wanna achieve.
    46/18=69" running 32c tires
    47/18=69" running 23c tires

  7. #7
    Senior Member
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    Yes they can both be 69" gears depending on wheel size. They're really close of course.

  8. #8
    King of the Hipsters
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    The typical factory fixed gear comes with a 48t chain ring and a 16t cog, which, with 700X23 wheels and tires, corresponds to 78.8 gear inches.

    The phrase gear inches refers to the amount of effort required to pedal a Penny Farthing Big Wheel bike having, in this case, a 78.8 inch diameter Big Wheel.

    The original poster's 50 X 16 setup, with 700X23 tires and wheels, comes out to 82.1 gear inches.

    I have ridden an 82 gear inch setup in an mixed urban/suburban/rural community having a dynamic gain and loss of about 1000' with success.
    I can't brake going downhill by back pedaling at 82 gear inches.

    I personally, in my riding area, consider 72 gear inches the most versatile gear set up for me and my riding area.
    I can brake going downhill by back pedaling at 72 gear inches.

    50 X 18 makes 73 gear inches.

    I presently ride 42 X 19, which makes 58 gear inches, as part of a learning experiment.
    Mucho spin.

    =====

    Sheldon Brown maintains an online gear calculator.

    http://sheldonbrown.com/gears/

    Make sure to select the proper tire size, crank length (not so important), and gear inches (as opposed to gain ratio.

    =====

    A more usable online gear calculator exists.
    I got the link from a thread on this forum.
    Rabbit?
    Anyway, I write from work and don't have it bookmarked on this computer.

  9. #9
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  10. #10
    Senior Member 1fluffhead's Avatar
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    This is the gear table that I like.
    http://www.ctc.org.uk/resources/Abou...e/GEARTABL.XLS It's an excel spreadsheet that changes the values when you change the tyre section box to reflect what size tyre you want.

    Got it from here:http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3521

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