Image Source: (YADAV, SINGH VERMA ,and Farkya, 2015)
“The gears on the back of your bike are generically referred to as a cluster, but there are really two totally different systems - freewheels and cassettes ”
The rear cogs (gears) are attached to the hub by two different hub systems:
Cassette hub/freehub
Freewheel
Although cassettes and freewheels perform the same function (allow you to coast when you stop pedaling) and look almost identical, they have significant mechanical differences and are NOT interchangeable.
What is the main difference between freewheel and cassette hub?
The freewheel is a single-unit and the act of pedaling tightens the freewheel to the hub. Whereas the cassette hub is a set of gears (cogs) that slides onto a cassette and is held in place by a lock ring.
Both the cassette and freewheel have a FreeHub, which is responsible for coasting.
“The freehub allows the bike to “freewheel” - to coast without engaging the gears ”
cassette hub/freehub/unit hub
“The concept of a ‘cassette’ or unit hub was devised and manufactured by British company Bayliss-Wiley in 1938 and won the Cyclists Touring Club (CTC) award for that year”
- Free Hub - The first widely successful commercial cassette hub was developed in 1978 by Shimano. Free Hub is a registered trademark of Shimano.
Freewheels
“An alternative system to the cassette and freehub is the “freewheel””
Before the 1980s, nearly all bicycles used the screw-on freewheel system. With this hub system, the cogs are attached directly to the hub. As the cyclist pedals, the freewheel is continuously kept tight due to the chain torque.
Two main drawbacks of freewheels:
Removing the freewheel is one of the main drawbacks of this system as the high torque from pedaling tightens the freewheel to the hub
The bearings are closer together, which equates to lessened leverage compared to the cassette (the cassette is stronger)
- Freewheel is both a verb and a noun. As a verb, “freewheel” means “to coast.”
Descending before the ability to “freewheel.”
Freewheels:
- Found on entry-level bikes (less expensive)
- Vintage bikes use the freewheel hub system
How to know if you have a freewheel or cassette??
The simplest way to know if you have either a freewheel or cassette is to look at the rotating action of the innermost tool fitting:
Take off the back wheel
Spin the gears backward
Cassette = tool fitting spins along with the gears
Freewheel = tool fitting does NOT rotate along with the gears
*** Look for the innermost tool fitting as some rings will have several tool fittings
Jesse is the Director of Pedal Chile and lives in Chile’s Patagonia (most of the year). Jesse has a Master of Science in Health & Human Performance and a Bachelor of Science in Kinesiology. Hobbies: Snowboarding, reader of non-fiction, researcher, & rides MTBs with cassettes.
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Sources:
Brown, Sheldon. “Freewheel or Cassette?” Www.Sheldonbrown.Com, 2 Aug. 2020.
C Calvin Jones (2013). Big blue book of bicycle repair : a do-it-yourself bicycle repair guide from Park Tool. Saint Paul, Mn: Park Tool Co.
C Calvin Jones (2019). Big blue book of bicycle repair : a do-it-yourself bicycle repair guide from Park Tool. Saint Paul, Mn: Park Tool Co.
King, Dave, and Michael Kaminer. The Mountain Bike Experience : A Complete Introduction to the Joys of off-Road Riding. New York, Henry Holt And Company, 1996.
Park Tool. (2017). Determining Cassette / Freewheel Type. [online]
Wiggins, Christopher. Bike Repair & Maintenance. New York, New York, Usa, Alpha, A Member Of The Penguin Group (Usa) Inc, 2014.
YADAV, R., SINGH VERMA, N. and Farkya, P. (2015b). Performance of Hybrid System for Automobile. Innovare Journal of Engineering & Technology, 3(1).