Thread: Help calculating differences with changing cogs
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Old 05-15-15 | 07:53 PM
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BlazingPedals
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Originally Posted by welshTerrier2

So, given your 20t setup, you would have 20 inches * 42t/20t = 42 gear inches

This means that for each revolution of the pedals (in those gears), the bike will move forward 42 inches.
Nope, the gear inches are the equivalent diameter of a tire if it were using a 1:1 drive (tricycle wheel.) The development is how far you'd travel, which is the gear inches times pi.
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