Cassette Sprockets

A bicycle cassette is a cluster of sprockets mounted on the rear hub of the bike, slotted into the body of the free-hub and kept securely in place with a threaded cassette lock. Typical cassettes may have anywhere between five and 13 sprockets, but most modern bicycle drivetrains use only 9, 10 or 11.

A profiled wheel with teeth or cogs is a sprocket, sprocket-wheel or chainwheel that is meshed with a chain, track, or other perforated or indented material. The term ‘sprocket’ usually refers to any wheel on which a chain passing over it is engaged by radial projections.