Gearing Up” Handout

Bicycles have a bewildering assortment of gears on them. But what are all those gears for? Let’s explore how the gears on a bike work.

Part 1
The pictures below show you some of the basic parts of a bicycle. There are two places on a bike where gears can be found. The front gears (also called the “chainwheels”) are attached to the pedal arms (which hold the pedals out at their ends). Then there are gears attached to the rear wheel’s hub. All the rear gears are contained in a cluster of gears on a “freewheel,” which only turns the rear wheel when you pedal forward. It is “free” of the wheel if you pedal backwards. The two sets of gears are connected by the bicycle’s chain. All the gear teeth are the same size. Why must this be the case?