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  1. #1
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    Need Lower Gears: Is 1 tooth enough?

    I normally run a 34/20 on a 29er and find it works well for me. However, I'm finding that after spending Fall at my desk rather than on the trail, I'm heavier and weaker than I like being. Rather than resorting to derailleur dependence, I figured I'd just thow on a bigger cog. Problem is I can't decide whether to add one tooth or two. Does anybody have any experience with chaning their gearing by one rear tooth? Is it enough to even make any differnece?
    Fat, tired.

  2. #2
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    Quote Originally Posted by farley
    I normally run a 34/20 on a 29er and find it works well for me. However, I'm finding that after spending Fall at my desk rather than on the trail, I'm heavier and weaker than I like being. Rather than resorting to derailleur dependence, I figured I'd just thow on a bigger cog. Problem is I can't decide whether to add one tooth or two. Does anybody have any experience with chaning their gearing by one rear tooth? Is it enough to even make any differnece?
    I don't really notice a 1 teeth difference. It's more a mental thing for me. 2-3teeths and I start to notice a difference.

    I would recomment you to keep your 34/20.

  3. #3
    CB2
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    That one tooth is almost 2 1/2 gear inches, and I'd notice that.
    I tried an experiment this past Fall, increase my gear inches by only 1 1/2" (change my chainring from a 32 to 33), and I noticed it.
    I went back to the 32 because I couldn't spin the 33 up as quickly as I liked.

  4. #4
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    I'm with CB2 -- I'd certainly notice a 1-tooth difference.

    I believe the more I ride my bike, the more familiar with its "usual feel" I get. If you really haven't been riding much, I say go up 2 teeth.

    --Sparty
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    We get old because we quit riding.

  5. #5
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    Having not glanced at the gear charts (sheldon browns site) in awhile.... ON motorcycles the small sprocket is usually in the front and the large in the rear. Going up 2 in the rear (big) is roughly equal to going down one in the front (small). If you add a tooth to the rear, while noticeable for most (usually in rpm/cadence) effort required will change very little. Going down two in the front for you will provide a bigger change in effort and a radical change in rpm noticed on flats and downhills. 34-20 is not a real tough gear and if your goal is to get in shape quickly I would stick with it. It will be difficult to clear stuff and you will be winded more often at first- but you will catch up to your buddies sooner in the season instead of languishing with easy gears for six months then switching and making it hard for you again. Secret- when I am off the biek for extended periods due to my travel schedule- I hit spin classes at the gym. THe scenery is spectacular sometimes and it is the fastest way to get in SS shape without walking up a bunch of hills, bike in tow!
    Vassago Cycles, Shadetree Bikes, Flat Tire Bikes, Galfer Brakes USA

  6. #6
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    Quote Originally Posted by cstem
    ... If you add a tooth to the rear, while noticeable for most (usually in rpm/cadence) effort required will change very little. Going down two in the front for you will provide a bigger change in effort and a radical change in rpm noticed on flats and downhills. ...
    I ride motorcycles, too. The comparison between gearing of motorbikes and pedal bikes isn't applicable because of the disparity between wheel size, engine speed & horsepower. On a 26" wheeled singlespeed bicycle, the difference between going up 1 tooth on the cog or down 2 teeth on the ring is practically negligible.

    Current gear = 34x20 = 44.2 gear inches
    +1 tooth on cog = 34x21 = 42.1 gear inches
    -2 teeth on ring = 32x20 = 41.6 gear inches

    That's only 1/2 gear inch difference between the two mods, which would hardly be noticeable to the average rider.

    --Sparty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  7. #7
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    IMO,if you've been off the bike fer a while,and yer havin probs spinnin the current gear,you prolly won't notice a 1t change.if'n ya been ridin a lot,and yer used to the normal feel of the bike,ya should notice.i'd go 2-3 if'n it were me,but thas me

    ps:keep yer gear when ya takes it off,and when ya gits back inta SS shape,ya can always put it back on

    steve
    '11 Origin 8 700CX
    '14 Surly Troll

  8. #8
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    Gear calcs above are for a 26" wheel... 34/20 is about a 49-inch gear on a 29'er.
    32/20 = 46.4 inches
    34/21 = 47 inches
    34/22 = 44.8 inches
    The 32t front option is a nice 5% reduction in effort to get back into shape... If it's really hilly where you are, the 22t rear option may be nice to have if there are some climbing epics that you find you walk a lot of the climbs... Just keep the 20t in the toolbox for later!
    R.I.P. Corky 10/97-4/09
    Disclaimer: I sell and repair bikes for a living


  9. #9
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    Basically, for a 29er 1 tooth in the back is ~2 teeth in the front. I would notice that. Just go ride a lot for a week and you'll be fine. If you commute by bike you'll always be in shape.

  10. #10
    time to climb
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    Don't do it mate. Hell, it's a new year . . . just drink one less beer each day, then buckle down and mash till your lungs are burning. It'll only last a few weeks, and you'll be stronger for it.

    Paulie

  11. #11
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    You will notice 1 tooth, mostly in a cumulative way, like after accelerating out of a series of corners, or in the second half of a ride.
    That said, I agree that you should just keep what you have and adapt to it. Better yet, go 2 gears smaller so you really have to crank for a couple weeks, then go back to your current setup and feel like a champ!

  12. #12
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    The correct gear ratio is a function of both fitness AND terrain. I run a 32/21 and also tried 32/20 and 32/22 (with 29er wheels). I could tell the difference between the three ratios and the 32/21 works best for me where I ride. That might seem like too low of a gear to some people, but I don't ride flat terrain much at all - it's either up or down. If I got stronger I would just go faster rather than gear the bike harder. So I say, go ahead and gear it down and see if it works for you. Start with a 1 tooth change and see how it feels.

  13. #13
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    No, it ain't lo

    Quote Originally Posted by Thor29
    ... 32/21 works best for me where I ride. That might seem like too low of a gear to some people, but I don't ride flat terrain much at all - it's either up or down. ...
    Well put, T29.

    One of the best riders I know (rides a tasty Wolfhound 29er & possesses mad skills) runs 32x21. He moved here (Orygun) ~10 months ago... can't remember where he used to reside but is was much flatter -- he used to run 32x17 no problem back there. Whoa -- 4 tooth dif on the cog.

    As you say, local terrain + fitness level = appropriate gearing. It wouldn't be right to assume an individual on an international web forum is a slug because he runs a lower gear than any other individual. Personally, I'm running 36x24 now (29er), which is even lower than your 32x21. I feel no shame.

    --Sparty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  14. #14
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    You'll notice it on the flats but if you've been having issues with some climbs I don't think one tooth will do it.

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