What Is a Bicycle Freewheel? Freewheel vs Cassette Explained
A bicycle freewheel is a rear drivetrain component that contains a set of sprockets together with a built-in freewheeling mechanism. It allows the rider to pedal the bicycle forward while allowing the rear wheel to continue rotating when the rider stops pedalling.
What Is a Bicycle Freewheel?
A bicycle freewheel is a component fitted to the rear wheel of certain geared bicycles. It combines the rear sprockets with a freewheeling mechanism in one assembly.
The freewheel is part of the bicycle drivetrain and works with the chain, crankset and shifting system to provide different gear ratios.
When the rider stops pedalling, the freewheeling mechanism allows the rear wheel to continue rotating without forcing the pedals to rotate at the same time.
Freewheel Anatomy
A multi-speed freewheel contains several rear sprockets combined with its freewheeling mechanism.
- Rear sprockets
- Freewheel body
- Threaded mounting system
- Internal freewheeling mechanism
The exact construction depends on the freewheel design and bicycle drivetrain.
What Are Freewheel Sprockets?
The sprockets on a multi-speed freewheel have different sizes. These different sprocket sizes create different gear ratios.
The larger rear sprockets provide lower gearing that can be useful for climbing, while smaller sprockets provide higher gearing for suitable faster riding.
How Does a Freewheel Work?
A freewheel contains a mechanism that allows the drivetrain to drive the rear wheel when pedalling, while allowing the rear wheel to rotate independently when the rider stops pedalling.
This is why the pedals do not have to keep rotating whenever the bicycle is moving forward.
Freewheel vs Cassette
Freewheel and cassette systems both provide rear sprockets, but their construction and mounting systems are different.
| Feature | Freewheel | Cassette |
|---|---|---|
| Construction | Sprockets and freewheeling mechanism are combined. | Sprockets mount onto a compatible freehub body. |
| Mounting | Threads onto a compatible rear hub. | Slides onto a compatible freehub body. |
| Freewheeling mechanism | Built into the freewheel assembly. | Located within the compatible freehub system. |
| Identification | Check the rear sprocket and hub construction. | Check the cassette and freehub construction. |
Freewheel Mounted on Rear Wheel
A freewheel is mounted onto a compatible threaded rear hub. On a multi-speed bicycle, the chain moves between the freewheel sprockets during gear changes.
The freewheel therefore forms an important part of the rear drivetrain.
Freewheel and Rear Hub
Unlike a cassette, a traditional freewheel threads directly onto a compatible rear hub.
This mounting difference is one of the easiest ways to understand the basic distinction between a freewheel and cassette system.
Single-Speed Freewheel vs Multi-Speed Freewheel
Uses one rear sprocket and is commonly found on simple single-speed bicycle setups.
Uses multiple rear sprockets and works with a compatible shifting system.
Freewheel Gear Range
The gear range of a multi-speed freewheel depends on the number and size of its sprockets.
Larger rear sprockets provide lower gearing, while smaller rear sprockets provide higher gearing. The useful range depends on the complete bicycle drivetrain and riding conditions.
How Does the Chain Move Across a Freewheel?
On a multi-speed bicycle, the rear derailleur moves the chain between the available freewheel sprockets.
The rider controls this through the gear shifter. The selected sprocket changes the rear gear ratio.
Complete Freewheel Drivetrain
The freewheel works as part of the complete bicycle drivetrain. The shifter, derailleur, chain, crankset, rear hub and freewheel all work together to transfer pedalling power and change gears.
Freewheel on MTB, Hybrid and City Cycles
Freewheel systems can be found on various bicycle configurations. The exact component depends on the bicycle model, drivetrain design and intended use.
Some older or simpler MTB drivetrain configurations can use multi-speed freewheels.
Some hybrid bicycles use compatible freewheel-based drivetrain systems.
Simple city bicycles may use single-speed or multi-speed freewheel setups.
Depending on the model, simpler drivetrain configurations may use freewheel systems.
Freewheel Wear and Replacement
Freewheel components can experience wear over time depending on mileage, riding conditions, chain condition, maintenance and usage.
Skipping, poor shifting or visible sprocket wear may indicate that the drivetrain needs inspection.
The chain, freewheel, derailleur and other drivetrain components should be checked together before replacing a part.
How to Choose the Right Freewheel
Match the freewheel to the bicycle's compatible drivetrain and number of sprockets.
Consider the smallest and largest sprocket sizes.
Make sure the freewheel matches the compatible threaded rear hub.
Consider the chain, derailleur, shifter and other drivetrain components.
Freewheel vs Cassette: Which One Does Your Bicycle Have?
The easiest way to identify the system is to inspect the rear sprocket and hub construction. A freewheel contains the freewheeling mechanism within the sprocket assembly, while a cassette mounts onto a separate freehub body.
If you are unsure, check the bicycle's specifications or have the rear drivetrain inspected by a bicycle technician.
Where to Buy a Bicycle in India?
If you are looking for a bicycle with a geared drivetrain, explore the VD Chawla Cycles Collection and check the complete product specification before buying.
For MTB bicycles, explore the MTB Cycles Collection .
For bicycle sizing, use the Cycle Size Guide before selecting a bicycle.
Explore bicycles and check the complete drivetrain specification before buying.
Explore CyclesFrequently Asked Questions About Bicycle Freewheels
A bicycle freewheel is a rear drivetrain component containing sprockets and a built-in freewheeling mechanism.
A freewheel allows the drivetrain to drive the rear wheel while also allowing the rear wheel to continue rotating when the rider stops pedalling.
A freewheel combines the sprockets and freewheeling mechanism into one assembly, while a cassette mounts onto a compatible freehub body.
A multi-speed freewheel contains multiple sprockets that provide different rear gear ratios.
A single-speed freewheel has one rear sprocket combined with a freewheeling mechanism.
A freewheel can be replaced when the replacement is compatible with the bicycle's rear hub, drivetrain and speed configuration.
Inspect the rear sprocket and hub construction. If you are unsure, check the bicycle specification or consult a bicycle technician.
Shimano has produced bicycle drivetrain components including freewheel products. The exact component should be identified from the bicycle's specification.
Useful Resources
Conclusion
A bicycle freewheel is an important rear drivetrain component that combines sprockets with a freewheeling mechanism. Understanding its anatomy, gear range, rear-wheel mounting system and differences from a cassette makes it easier to understand bicycle gears and drivetrain components.