Cog

Sheldon Brown's Bicycle Glossary · letter C
← Cobalto ® Brake (Campagnolo) · Columbus →

Popular term for a rear sprocket. Sometimes incorrectly used as a synonym for cluster, which is actually a group of cogs.

Originally, "cog" referred to just a single tooth on a "cog wheel." Then "cog wheel" was shortened by popular usage to "cog."

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