Differences Between a Freewheel & a Cassette

Both the cassette and freewheel appear as a pyramid of cogs stacked side-by-side on a bicycle. The two designs even function similarly. By containing cogs of various size, both designs provide the cyclist with multiple gears, called "speeds." Only during disassembly of a cassette and freewheel do the differences between the two become readily apparent. Recognizing these differences is crucial to properly servicing either device.

  1. Freewheel Description

    • The predecessor of the modern cassette, the freewheel is comprised of a series of cogs mounted around a ratcheting body assembly. This assembly allows the cogs to spin independently of the hub. This feature provides the cyclist with the option of coasting -- riding without pedaling. Generally, the number of cogs included on a freewheel range between 5-7. The freewheel's internal threads match threads located on the bicycle's rear-wheel hub. The freewheel attaches to this hub.

    Cassette Description

    • Unlike the freewheel, the modern cassette consists of a cluster of cogs only. Rather than part of the cog assembly, the ratchet mechanism has been incorporated in the body of the wheel's hub. Modern cassettes generally contain 7-10 cogs. A pattern of splines inside the cassette match an identical pattern on the body of the hub. The cassette slides onto the hub and is kept in place by a lockring.

    Freewheel Removal

    • Bicycle mechanics remove freewheels and cassettes periodically for servicing procedures. Freewheel removal involves the use of a specially designed tool, called a "freewheel remover." Once the mechanic inserts the freewheel remover into the side of the freewheel, he then uses a wrench to rotate the freewheel remover counter-clockwise. The counter-clockwise action unscrews the freewheel from the side of the hub.

    Cassette Removal

    • Like the freewheel, removal of a cassette requires at least one tool specially designed for the procedure. The mechanic installs a "cassette remover" into the side of the cassette. Using a "chain whip" to keep the cassette from rotating, the mechanic then employs a wrench to rotate the cassette remover counter-clockwise. Unscrewing the loosened lockring from the side of the cassette, the mechanic lifts the cassette from the hub.