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  1. #1
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    Thoughts on braking with fixies, in regards to gear inches...

    I'm at around 76 gear inches right now.

    42t/16t * 29" = 76.125 gear inches


    This is the only fixed gear bicycle I've ever ridden, and the braking is pretty good.

    My question is. . . . If I move to a bicycle with smaller wheels, such as....

    52t/13t * 14" = 56 gear inches

    Is the increased RPM offset by the shorter gear inches, meaning that it will require virtually the same amount of effort to backpedal (i.e. - brake by resisting forward movement)???

    If speed is constant between the two bikes, is ease in braking constant as well??!?!?

  2. #2
    . xavier853's Avatar
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    in before "get a brake lever"

  3. #3
    Senior Member Bat56's Avatar
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    ThIs is why gear inches are so 1990. Gear ratio is where its at.

  4. #4
    Just smang it. EpicSchwinn's Avatar
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    Quote Originally Posted by xavier853 View Post
    in.. . . before "get a brake lever"?!?!?!!??!?
    ftfy!!

  5. #5
    You gonna eat that? Doohickie's Avatar
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    Try to find 14" wheels, I dare ya.
    I stop for people / whose right of way I honor / but not for no one.



    Originally Posted by bragi "However, it's never a good idea to overgeneralize."

  6. #6
    Just smang it. EpicSchwinn's Avatar
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    I'm a little curious about the brakeless 29er to be honest.

  7. #7
    ÖöÖöÖöÖöÖö Dannihilator's Avatar
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    No.

    Get a brake and a more sensible gear ratio. You most likely will not have clearance on a 29er frame for a 52 tooth chainring. Plus the gear inches a 52x13 is with a 29er wheel is 116.5, you would be miserable with that gearing.
    Strike like an eagle and sacrifice the dove.
    Words and Stuff.

  8. #8
    I am ill Decepticondc5's Avatar
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    There is no way he is talking about the same frame here. Bike 1 is a 29er i assume. Is bike 2 one of those mini-velo bikes?

  9. #9
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    Yes, two totally separate frames.

    The second is a folding bike w/ 14" wheels. I met a guy with two of 'em brand new. They're called Roll N Fold. Not the best welds, but somebody else here, "James Haury", said he was able to upgrade the gearing to 52t & 13t fixie. Just uses red loctite, I'm supposing... but I'll use a [non-reverse threaded] lockring, too!!!

    I'm not going to be hauling tail downhill with this thing, but I'm just wondering how the gear inches will play on stopping at the same rate of speed on these two entirely different setups....

    Shorter gear inches = higher cadence, but easier to backpedal???

  10. #10
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    Quote Originally Posted by Bat56 View Post
    ThIs is why gear inches are so 1990. Gear ratio is where its at.
    Gear ratio only tells HALF the picture. Wouldn't you agree, considering you clearly missed the ENTIRE point of this thread?

    Quote Originally Posted by EpicSchwinn View Post
    I'm a little curious about the brakeless 29er to be honest.
    It's just a Motobecane Outcast w/ this seat, but it DOES have both hand brakes.

    The 14" folding bike that I'm looking at has front and rear u-brakes, but I'm trying to get a feel for how braking should work if I were to remove them, at least temporarily.

    Quote Originally Posted by Dannihilator View Post
    No.

    Get a brake and a more sensible gear ratio. You most likely will not have clearance on a 29er frame for a 52 tooth chainring. Plus the gear inches a 52x13 is with a 29er wheel is 116.5, you would be miserable with that gearing.
    You can't read gear inches either?? It's really not difficult.

    One more time...

    If speed is constant between the two bikes, is ease in braking constant as well??!?!?

  11. #11
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    Quote Originally Posted by grndslm View Post

    If speed is constant between the two bikes, is ease in braking constant as well??!?!?
    Here's what a little thinking did for me.

    If one bike has a lower gear ratio, it will have better acceleration from a stop. That process in reverse, coming a stop from a constant speed, will be easier by the same factor. Both are acceleration, so the degree of ease will be the same if you are accelerating forwards or backwards (slowing down).

    My two cents.

  12. #12
    Just smang it. EpicSchwinn's Avatar
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    Quote Originally Posted by grndslm View Post
    You can't read gear inches either?? It's really not difficult.
    Then sit down and figure it out yourself. Obviously nobody here knows as much about bikes or gearing as you do.

  13. #13
    Fresh Garbage hairnet's Avatar
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    We can talk and talk but it wont make a difference until you try it. Lower gear inches should povider easier starting/stopping
    Quote Originally Posted by Scrodzilla View Post
    I'd rather ride a greasy bowling ball than one of those things.
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    Senior Member Hothead286's Avatar
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    Quote Originally Posted by grndslm View Post
    Shorter gear inches = higher cadence, but easier to backpedal???
    Yes, also easier to pedal forward.

  15. #15
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    Quote Originally Posted by EpicSchwinn View Post
    Then sit down and figure it out yourself. Obviously nobody here knows as much about bikes or gearing as you do.
    I don't have the second bike to compare it yet.

    Still deliberating and determining all my options before I decide.

  16. #16
    Fresh Garbage hairnet's Avatar
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    anyway, 56 gear inches is super low. I rode around for a while with 60gi fixed and it wasnt very good for much speed and I spinning too much for comfort down slight grades. If you're going go for this folding bike consider installing a SS freewheel
    Quote Originally Posted by Scrodzilla View Post
    I'd rather ride a greasy bowling ball than one of those things.
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  17. #17
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    leverage.

    small ring, big cog = easy get up and go and easy skid.

    big ring, small cog = slow acceleration and hard skid.

    so measure the diameter of your cogs and figure out the ratio between it and the wheel (with tire) diameter. Now figure out the ratio of the crankarm length to chainring radius(? center of ring to top of tooth valley).

    If the numbers are equal then itll prob be the same.

    those small wheel bikes ride like skateboards. ROUGH.

  18. #18
    I am ill Decepticondc5's Avatar
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    if it werent finals week i would calculate this out in terms of efforts and flows and get a real answer. System Dynamics is raping my life right now.

  19. #19
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    Quote Originally Posted by hairnet View Post
    anyway, 56 gear inches is super low. I rode around for a while with 60gi fixed and it wasnt very good for much speed and I spinning too much for comfort down slight grades. If you're going go for this folding bike consider installing a SS freewheel
    I repeat... NO HILLS. NO INCLINES.

    This is more a type of bike I'll keep in my trunk for emergencies, riding around some shopping centers, at friends' apartment complexes, and other short trips. Not planning on riding more than 5 miles or so at a time. I've gone 15 or 20 mi. on a BMX with around the same gearing (55 gear inches) as this 14" bike.... but the BMX wasn't a fixie. Hence, this thread to see how a fixed 20" compares to a fixed 29" with similar gearing...

    Quote Originally Posted by gottliver View Post
    leverage.

    small ring, big cog = easy get up and go and easy skid.

    big ring, small cog = slow acceleration and hard skid.

    so measure the diameter of your cogs and figure out the ratio between it and the wheel (with tire) diameter. Now figure out the ratio of the crankarm length to chainring radius(? center of ring to top of tooth valley).

    If the numbers are equal then itll prob be the same.

    those small wheel bikes ride like skateboards. ROUGH.
    Hmm... I will have to look into this diameter ratio thing once I get the bike. It'll prolly take me a couple months to converting it to fixed if I even get it.

    But $100 says you're wrong about the small wheels making it ride like a skateboard...

    - http://www.ebay.com/itm/REAL-Leather...item5646ea8f2c

    Or how about $30??

    - http://www.amazon.com/Planet-Bike-An.../dp/B000U7NU1Y

    Quote Originally Posted by Decepticondc5 View Post
    if it werent finals week i would calculate this out in terms of efforts and flows and get a real answer. System Dynamics is raping my life right now.
    That would be sweet....

    I'd figure that Lao_shi's answer would be most correct. Gearing relates to acceleration & speed. Just reverse the direction, and the shorter gear inches will lead to an easier stop if both bikes are traveling at the same rate of speed [even tho it will look to be spinning quite a bit faster]. That was my guess, but I'd figured this would be a common understanding by almost 2012.

  20. #20
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    Quote Originally Posted by EpicSchwinn View Post
    I'm a little curious about the brakeless 29er to be honest.
    Good way to tear up/ruin trails.
    Quote Originally Posted by Santaria View Post
    because physics has more street cred than tarckstars.

  21. #21
    Senior Member nuhtowel's Avatar
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    why do you even want to make this a fixed gear? I bet turning will be fun on that thing.

  22. #22
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    Quote Originally Posted by ianjk View Post
    Good way to tear up/ruin trails.
    What trails?

    Quote Originally Posted by nuhtowel View Post
    why do you even want to make this a fixed gear? I bet turning will be fun on that thing.
    What's "this"? Turning will be fun on what "thing"??

  23. #23
    Just smang it. EpicSchwinn's Avatar
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    I hope you don't become a regular here. Condescending trolls can gtfo.

  24. #24
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    Quote Originally Posted by EpicSchwinn View Post
    I hope you don't become a regular here. Condescending trolls can gtfo.
    Seriously.

  25. #25
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    I asked honest questions.

    We are on entirely different pages.

    You're talking about gear ratios; I'm talking about gear inches.
    You're talking about 1 bike; I'm talking about another.

    Soo... again, "WHAT" do I want to make into a fixed gear??

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