The bicycle chain connects the crankset to the rear sprockets, allowing you to pedal and shift gears. It is the most important mechanical component of a bike, and its durability has a direct effect on the rider’s comfort and performance. The chain is made up of outer and inner plates held together with pins (or rivets) and a roller. There are a variety of chain designs, from the bar-link chain that looks like something a six-year-old might draw to the more complicated, multi-speed chains used on modern racing bikes.
Most modern chains are designed to work as a system with the drivetrain, including the derailleurs and rear sprockets. Manufacturers tinker with design elements such as side plate shape, size and height, pin width and length to improve shifting performance or meet specific market demands.
In addition to lubrication, the condition of a chain can be dramatically affected by how it is used and maintained. Riding a hard cadence and crossing-chaining (using the small chainring and large cog on the front, or the large chainring and small cog on the rear) significantly shortens a chain’s lifespan.
Cleaning a chain with solvents also drastically reduces its life. Most cleaners attack the lubricating film inside the chain, which must be replaced to keep the chain running smoothly. This process interrupts lubrication, causing the rivets to wear away and the outer plates to become brittle.