Freewheel? Cassette? Freehub? Ever heard of them?
They’re vital components on a bike. So if you don’t know (or want to learn more) you’re in the right place!
On any bike, there is a set of multiple sprockets that attaches to the hub on the rear wheel. The rear cogs consist of one of two different systems: freewheel vs cassette.
Although cassettes and freewheels perform the same function, (i.e. they both allow you to coast when you stop pedalling) they have significant mechanical differences and are not interchangeable.
Despite this, the terms “freewheel” and “cassette” are often used interchangeably — which can be a costly mistake if you get your hardware in a muddle.
Fortunately, this is a hub for knowledge on everything to do with freewheel and cassette hubs.
- Freewheel Vs Cassette: What Is A Freewheel?
- Freewheel Vs Cassette: What Is A Cassette?
- What Is A Freehub?
- What’s The Difference Between A Freewheel Vs Freehub?
- What’s The Difference Between A Freewheel Vs Cassette?
- The Pros And Cons Of A Freewheel Vs Cassette
Sound good? Then let’s get right into it…
Freewheel Vs Cassette: What Is A Freewheel?
Let’s start with definitions…
A freewheel consists of either a single sprocket or a set of sprockets mounted on a body containing an internal ratcheting mechanism that mounts directly onto a rear threaded hub.
Just to be clear, “freewheel” is both a noun and a verb. As a verb, “to freewheel” is to coast and roll on your bike without pedaling. As a noun, “freewheel” refers to the physical block of cogs that screws onto the threads of the rear wheel.
Freewheels were pretty much the standard for all bikes made up until the late 1980s.
Until then, the ‘screw-on’ freewheel systems were the standard for nearly all bicycles. 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.
Freewheel Vs Cassette: What Is A Cassette?
A cassette is a cluster of sprockets located on the rear hub, slotting in with a “freehub” (more on this later) and held in place with an integrated lockring, to keep the cog in place and prevent it from falling off while riding.
Cassettes sound simple but there’s a lot of engineering that goes into a bike cassette.
Instead of being a collection of cogs, the sprockets in a cassette are designed to work together as a whole — the individual sprockets are positioned precisely close to each other to ensure the chain shifts smoothly between cogs.
Cassettes are available in different sizes. This is determined by the number of teeth on the largest cog.
The most common sizes on modern bikes are 10-speed, 11-speed, and 12-speed. Each size must match the size of the bicycle chain, as the chain will be a different width depending on what number of speeds it’s designed for.
These designs have gradually evolved over the years, but the first widely successful cassette hub was developed by Shimano in 1978. Today, cassettes are an essential part of the drivetrain for modern bikes.
Freewheel Vs Cassette: Key Differences
Let’s break down the main differences between freewheels and cassettes.
#1. Number of Speeds
Typically, a freewheel will have 5-7 different speeds, whilst a cassette usually has 7-12 different speeds.
#2. Design and Mechanism
The freewheel threads straight onto the rear wheel and has a group of gears. Contrastingly, the cassette is not threaded onto the rear wheel – instead, it slides onto the splines of the freehub, and is held in place with a lockring.
Freewheels are interchangeable, so any brand’s freewheel can be fitted on any freewheel-compatible hub.
Cassettes are not always interchangeable between brands, as they use different spline patterns on the freehub body. Shimano and SRAM (and some smaller manufacturers) use the same system, but Campagnolo has its own.
What Is A Freehub?
Much of the confusion between freewheel and cassette is largely due to the freehub.
A freehub is simply defined as a type of bicycle hub that incorporates a ratcheting mechanism. It’s what allows the wheel to rotate independently of the pedals (coasting).
How do they work? A cluster of sprockets (cassette) is mounted onto a splined freehub body to engage the chain.
The key difference between a freewheel and a freehub is down to where the coasting mechanism is situated.
On a freehub, the coasting mechanism is a sub-assembly of the wheel’s hub. The cassette (see above) slides into place on the freehub body and is held into place by splines and a lockring.
For freewheels, the coasting mechanism is built into the gear cluster. When we use the term “freewheel”, we’re referring to the whole gear cluster with the coasting mechanism inside.
The freewheel is screwed onto a set of threads located on the right-hand side of the wheel’s hub.
Essentially, freewheels and freehubs are different ways of accomplishing the same thing. But – crucially – they’re not interchangeable.
For example, if your freewheel wears down, you remove it and replace it entirely, including the stack of gear rings.
Whereas with a cassette, you can remove it without needing to replace the freehub too.
Freewheel Vs. Cassette: The Pros And Cons
So now we’ve broken down the differences between freewheels, cassettes, and freehubs, let’s take a look at the advantages and disadvantages between them.
The Pros Of Freewheels
You can use any brand of freewheel on a freewheel-compatible hub.
A relatively simple design means replacement parts are cheap (particularly for Shimano freewheels). Freewheels typically have lower upfront costs compared to cassettes.
#3. Style Points
If you’re really committed to that vintage, retro aesthetic, right down to the nuts and bolts, then a freewheel might be for you.
The Cons Of Freewheels
#1. Difficult To Remove
The high torque from pedaling tightens the freewheel to the hub, meaning, removing a freewheel mechanism is difficult and problematic.
#2. Fewer Speeds Available
Freewheels typically only have space for up to 7 gears, whereas modern cassettes can have as many as 13.
#3. Less Reliable
Freewheels generally need to be replaced more often than cassettes – and when they do, you replace the ratcheting mechanism as well as the cogs themselves.
The Pros Of Cassettes
#1. More Gearing Options
Cassettes can provide a wider range of gear ratios for your chain to run on, with smaller gaps between gears. This allows you to vary your pedaling cadence and achieve the optimal efficiency for the gradient or terrain you’re riding.
In general, cassette systems tend to break less at the axle than freewheels. Plus, cassettes are also good at mitigating issues with bent axles.
When the sprockets need to be replaced after some wear and tear, you only have to replace the sprockets themselves instead of the whole ratchet mechanism.
In addition, the drive-side axle bearing can be positioned nearer the frame rather than at the center of the axle behind the cassette. This significantly reduces the stress on the rear axle – meaning bent, broken, or damaged axles are rare.
#4. They’re Light
High-quality cassette and freehub combinations typically weigh less than an equivalent-standard freewheel.
The Cons Of Cassettes
The cassette mechanism is more complicated than a freewheel and involves more parts. There are more components that can go wrong.
#2. Loss of Interchangeability
Cassettes and freehubs are more proprietary between brands than freewheels.
Even when a cassette is compatible with the freehub splines of another manufacturer (e.g. Shimano cassette on a SRAM freehub), it might not have optimal performance if the rest of the drivetrain is from another brand.
Which Should I Use: Freewheel Vs Cassette?
Short answer: it depends on what kind of bike you’re riding.
Most classic or retro bikes come with freewheels, so if you’re a vintage bike fan – the choice might already be cut out for you.
Likewise, a modern road bike is very unlikely to be compatible with a freewheel.
The cassette is the latest technology and offers a wider range of gears and better shifting performance for more vigorous and challenging terrains.
In addition, cassettes offer experienced riders more performance advantages such as lower weight and reliability, which can be a dealbreaker in competitive or time-trial situations.