# Does anyone know where i can get a chart of bicycle gear differentials?

**URL:** <https://boards.straightdope.com/t/does-anyone-know-where-i-can-get-a-chart-of-bicycle-gear-differentials/252183>\
**Category:** Factual Questions\
**Created:** [June 25, 2004, 2:50pm UTC](https://boards.straightdope.com/t/does-anyone-know-where-i-can-get-a-chart-of-bicycle-gear-differentials/252183 "2004-06-25T14:50:43Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\
**Post date:** [June 25, 2004, 2:50pm UTC](https://boards.straightdope.com/t/does-anyone-know-where-i-can-get-a-chart-of-bicycle-gear-differentials/252183/1 "2004-06-25T14:50:43Z")

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I don’t know if differentials is the right word for it though. What i mean is if you have one full revolution of the pedals how many revolutions will the back wheel have in different gears?

It would preferably be a chart with different types of bicycle gearings too. non-geared bikes, 10 speeds, 15 speeds, 21 speeds, etc.

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**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\
**Post date:** [June 25, 2004, 3:04pm UTC](https://boards.straightdope.com/t/does-anyone-know-where-i-can-get-a-chart-of-bicycle-gear-differentials/252183/2 "2004-06-25T15:04:42Z")

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Hmm. i suppose i could just count the teeth on a bicycles gears and calculate them that way.

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**Author:** ![BF](https://avatars.discourse-cdn.com/v4/letter/b/b5ac83/32.png) [@BF](https://boards.straightdope.com/u/BF)\
**Post date:** [June 25, 2004, 3:52pm UTC](https://boards.straightdope.com/t/does-anyone-know-where-i-can-get-a-chart-of-bicycle-gear-differentials/252183/3 "2004-06-25T15:52:46Z")

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[Sheldon Brown to the Rescue](http://sheldonbrown.com/gears/)

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**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\
**Post date:** [June 25, 2004, 4:07pm UTC](https://boards.straightdope.com/t/does-anyone-know-where-i-can-get-a-chart-of-bicycle-gear-differentials/252183/4 "2004-06-25T16:07:54Z")

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For gear ratios you will have to consult the manufacturers.

Ask you local bicycle dealer he may help.

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**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\
**Post date:** [June 25, 2004, 4:34pm UTC](https://boards.straightdope.com/t/does-anyone-know-where-i-can-get-a-chart-of-bicycle-gear-differentials/252183/5 "2004-06-25T16:34:11Z")

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Wow! Spin gears. Up until now I had read **spingears** as sping ears. I had no idea what a sping was, but I figured it had ears. :smack:

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**Author:** ![Anachronism](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@Anachronism](https://boards.straightdope.com/u/Anachronism)\
**Post date:** [June 27, 2004, 11:29am UTC](https://boards.straightdope.com/t/does-anyone-know-where-i-can-get-a-chart-of-bicycle-gear-differentials/252183/6 "2004-06-27T11:29:53Z")

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Here is another gear calculator that gives lots of information – [http://www.panix.com/~jbarrm/cycal/cycal.30f.html](http://www.panix.com/~jbarrm/cycal/cycal.30f.html) . Typing gear calculator into a search engine should give you many to choose from.

If you simply want to know the number of revolutions the rear tire makes for one pedel revolution you could just divided the number of teeth on the front ring by the number of teeth on the rear gear.