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Gear ratios

  1. Feb 24, 2015 #1
    I'm confused as to how gear ratios work in bicycles. I'm given a problem which says that gear ratio = rfront/rear. It then says that the gear ratio changes from 4 to 0.7. Does this mean that the radii of the gears are changing? I'm unfamiliar with gears on a bicycle so I'm not sure if the radius of the gear can change,
     
  2. jcsd
  3. Feb 24, 2015 #2

    Svein

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    images?q=tbn:ANd9GcTihNh9C5plUKlxcOgm-hU0PTWT4QxV1HllZcBjWJcJ-Oqu3eD1.jpg
    Here is a picture of a bicycle gearing system. The rear wheel has a "rosetta" of 7 cog wheels with different diameters. The pedal setup has just two wheels with different diameters. The gear ratio is then (selected diameter at the pedal setup)/(selected diameter on the rear wheel rosetta).
     
  4. Feb 24, 2015 #3

    CWatters

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