What’s so free about a freewheel?

The freewheel (shown in Figure 11-1) is a part of a clutch-like system that was a significant advance in the design of bicycles. Older bikes are designed with freewheels that consist of individual cogs (toothed disks surrounding the hub on your rear wheel that combine to form the freewheel of your bike), bear­ings, pawls, pawl springs, and gears that are screwed directly on to the hub.

What's so free about a freewheel?

Figure 11-1:

A freewheel

What's so free about a freewheel?

One disadvantage to freewheels is that the force from pedaling can tighten them, making removal difficult. Another problem with freewheels is that, because of the spacing requirements, the bearings on each side of the hub are located closer together toward the center of the hub, while the axle is extended outward from the bearings to support the freewheel. As a result, the axle receives less support and can break or bend under the right amount of force.

If you have a traditional freewheel, when your cogs wear out you may want to think about converting to a cassette system (see the following section). If you do opt for a cassette system, your best bet is to replace the hub with a free hub. The alternative is to buy a freewheel hub and rebuild your wheel.