Shaun George Bike Skills, BOTS Guides, D.I.Y, Mechanics, Tips & Tricks

You’ve probably asked yourself. Does my bike have a cassette or a freewheel? It’s something our inner mechanic has always wanted to know. Both perform a very similar function, but there are a few fundamental changes to know about. Read on to geek out over the fundamental differences between cassettes and freewheels.

The rear cogs on bicycles are attached to the hub in one of two ways. The bike either has a freewheel or a cassette with a freehub. Both look very similar but function differently.


Freehub body and cassette

Newer bikes tend to use a hub type called a “cassette hub.” The cassette hub uses a “freehub” system, which is a type of clutch mounted to the body of the hub. This cylindrical mechanism ratchets counter-clockwise for coasting and locks clockwise for driving the bike when pedaled by you. The freehub body has a series of splines on the outer shell. The “Cassette” sprockets slide over these splines and that is what locks and holds them in place. A lockring threads into the freehub and holds the sprockets/cogs, in place. When the cogs are removed, the ratcheting freehub remains on the hub body. Most modern bicycles use this type of freehub system.


Freewheel and threaded hub
A Freewheel

Freewheels, on the other hand, are usually found on older bikes – they have a large external thread machined into the hub. The cogs and ratcheting body assembly together is called a “freewheel”, this freewheel threads onto the hub. The ratcheting mechanism comes off with the cogs when the freewheel unthreads for removal.


 Commonly 5, 6, or 7 speeds.Commonly 8, 9, 10 and 11 speeds.
The freewheel is an older version.Modern bicycles use cassettes nowadays.
They cannot mount the cassettes on a split freehub bodyMount the cassettes on a division freehub body
A group of gears that have a ratcheting mechanism built-into the cogs.A group of gears that have a ratcheting mechanism built-into the hub.
A freewheel threads onto the rear hub. A cassette is not threaded onto the rear hub.
Lower priced and still seen on new bikes usually using 7 or 8-speed freewheelsHigher priced and usually found on 9, 10 and 11 speed bike
Extractor splines do not rotate when you spin the sprocket backward.Here, the tool extractor splines also rotate with the cogs.


Both systems look quite similar from afar but these days it’s not that hard to identify one from the other. Mainly because freewheels aren’t that common anymore. Yes, many of the budget-friendly/children’s bikes still feature freewheels – simply because they reduce overall manufacturing costs. Chances are if you’ve got a new bike, it’s most probably got a cassette. But here are a few ways to be sure

  • Freewheel axles are typically recessed slightly into the axle.
  • Cassettes are typically flush with the face of the gears, and you can see the splines around the perimeter.
  • Freewheel axles may also show splines, but not as many as a cassette, and are recessed into the body deeper, around the axle itself.
  • Not all Freehubs have a bulge, but whenever you see it, you can be sure that it is, in fact, a cassette Freehub.

Over the past few decades, the cassette replaced the conventional threaded rear hub. This newer style hub works so well that they have replaced the traditional freewheel and have become the new standard for contemporary road bikes, MTBs, and even Hybrids. One of the major differences between a freewheel and a freehub is the location of the coasting mechanism. It incorporates the ratchet mechanism into the hub body, so you can replace only the sprockets, rather than the ratchet mechanism. Unlike the freewheel system, the lockring splines will turn with the sprockets when spun backward (easiest way to tell if it’s a cassette or sprocket).

Watch this video by Park Tool to further understand cassettes and freewheels-

It’s that simple! Hopefully, you’ve now understood the differences and will be able to spot one from the other immediately.

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