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Thread: Gearing

  1. #1
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    Gearing

    Ok, so I am no math wiz and haven't bothered to spend the time trying to calculate this out. I ride a 26r SS with a 32/18. For the most part this is fairly standard. But am I correct in saying that most of the guys rolling on 29's are also running the same gearing? If that is the case, doesn't that actually make it geared some what lower? I mean, would that maybe be the equivalent of me running say a 32/20 or am I wrong and it would be more like me riding a 32/16? Just curious. To me it would seem like it would take more crank rotations at the same gearing to make the 29er rotate one revolution than a 26er.

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    Quote Originally Posted by 1SPD
    Ok, so I am no math wiz and haven't bothered to spend the time trying to calculate this out. I ride a 26r SS with a 32/18. For the most part this is fairly standard. But am I correct in saying that most of the guys rolling on 29's are also running the same gearing? If that is the case, doesn't that actually make it geared some what lower? I mean, would that maybe be the equivalent of me running say a 32/20 or am I wrong and it would be more like me riding a 32/16? Just curious. To me it would seem like it would take more crank rotations at the same gearing to make the 29er rotate one revolution than a 26er.
    With an equal gear ratio a 29 inch wheel will be harder than the 26 inch.

  3. #3
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    Ok, after reading my own post, I confused myself. I was correct in my thinking and wrong in my typing. Thanks for the clarity on that.

    I can't imaging jumping to a 32/16 right now on my SS but perhaps that will come. I think it would be hell on some of my trails though but I guess if the guys on the 29's are doing it, I really don't have an excuse!

  4. #4
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    What you need to know is "gear inches" to calculate equivalency between a 26" wheel and a 29" wheel.

    For example: 32 x 19 on a 29er = 48.8". 32 x 19 on a 26er = 43.8".

    If you want to play with numbers try this: http://www.sheldonbrown.com/gears/

  5. #5
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    I use Sheldons tool all the time. Maybe even too much. I ride 34x16 on my 26er and just outfitted my new 29er with 33x18 q-ring config. Ordered a 17t cog just in case today, will see...

  6. #6
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    Using said calculator, I found this:
    26" wheel, 175 crank, 32x18= 46.2 gear inches
    29" wheel, 175 crank, 32x20= 46.4 gear inches

    I run 32x18 on my 26" rigid SS. It is the perfect gear for me and my trails. If there were less climbing in the area, I might try to pull off the 2:1 ratio.
    I believe many 29ers are running 32x20.
    -Chris

  7. #7
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    As noted previously, the only way to truly calculate the difference between you and your 29er buddies is to take into account their crank arm length as well. It gets a bit complicated; Sheldon Brown does a good explanation here in Gain Ratio: http://www.sheldonbrown.com/gain.html

    Most people use ratios for calculations, in your case 32/18 = 1.77 (less than 2:1 standard). As Sheldon discusses in the link above, this system is flawed because it does not take into consideration the wheel size and crank lengths.

    In general terms if you are equally matched on crank lengths, your assumption of them (29ers) riding the same gearing as your (26”) equates minus 2-teeth, is within close proximity. A good way to test this is to spin on your bike then on theirs.

    Also, here's the "Rabbit, a singlespeed and fixed gear calculator" which I find breaks it down the best: http://software.bareknucklebrigade.c...it.applet.html

  8. #8
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    You don't have to use the same gearing as everybody else.

    If you want to try taller gearing, a cog does not cost all that much.... If you hate it, put the 18T back on.

  9. #9
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    So to answer your question, no the 29ers do use the same gearing as 26" rider and yes a rider using 32:18 on a 26" would probably use a 32:20 on a 29er, which BurkeVT post proves out. For not being a math wiz, you fig'erd it out pretty dang close..
    Just one more rep and I get the toaster!

  10. #10
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    I run a 29er w/ rigid carbon fork and 2.35" tires. Early season I run 34x22, then starting mid-season (once my fitness and cardio get up to speed) I change the 22 to a 21. I ride a lot of big VT hill climbs in this setup. Works for me. Some riders I know run taller gears but I like to try to clean everything on climbs, and I like to ride for 2+ hours.

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