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Freewheel ?(2 posts)

Freewheel ?spinner
Apr 10, 2001 6:07 AM
Can somebody explain to me what a freewheel is, and it's advantage...etc... Thanks Scott
Freewheeling 101Marlon
Apr 10, 2001 9:32 PM
A freewheel is a device that allows you to coast on a bike. Essentially, it's a racheting mechanism that disconnects your cranks from your rear wheel - unlike a single speed track bike, the cranks on your commonly-seen road bike do NOT turn around when your rear wheel is moving, thanks to a freewheel-like mechanism.

Freewheels are actually an older design, now supplanted by freehubs (or cassette bodies) and casettes. The freewheel mechanism (called the freewheel body) was composed of all the internal gearing that allowed you to coast, and it had to be screwed on to the rear hub. A couple of problems with this: one, there was no widespread conformity or standardization between the various manufacturers of hubs and freewheels. Two, freewheels could be difficult to remove, as pedalling pressure tightened the freewheel onto the hub. Three, cog removal was often tricky. And four, they placed limitations on hub designs, because of the spacing requirements of the freewheel - hub bearings could only be a certain distance apart.

Enter the freehub and cassette.

The freehub, containing all the ratcheting and coasting mechanisms, is built as part of the hub. In fact, freehubs are more commonly just referred to as hubs. In any case, as the freehub is part of the hub, this allowa the hub bearings to be farther apart, which means more support for the axle, strengthening it. Also, cog removal is much easier - cogs are built up as part of a cassette, or stack of cogs, which slide onto the freehub (or cassette body) and can be locked into place using a lock ring. You can, in most cases, mix and match cogs into a cassette that you want.

Problems with casette bodies and cassettes? Um... Cramp-and-go-slow and Shim-and-go aren't compatible. Otherwise, life is fine.

End of discussion :)