At first glance, chains seem incredibly simple. This holds true regarding their function, but their design is more sophisticated than meets the eye. Chains are comprised of a repeating pattern of connected links, each of which is made of four individual pieces. These pieces–– the two side plates, a pin, and a roller–– are usually made of steel, and these pieces work in unison to transfer power and move across your gears with the help of the derailleur. As the individual parts of the chain are constantly moving against each other, they require cleaning and lubrication to cut down on friction and run more efficiently.