A crank in a bicycle is used to transfer power from the pedal to the chainrings and then to the rear wheel, thereby propelling the bike forward.
One practical use of a crank in a bicycle is to provide mechanical advantage and allow the rider to generate and transfer power to the drivetrain system. The crankset, which consists of crank arms and chainrings, connects the rider's legs to the bicycle's drivetrain and converts pedaling motion into rotational force. As the rider pushes down on the pedals, the crank arms rotate, and this rotary motion is transmitted through the chainrings to the chain, which then drives the rear wheel. The crank's design allows the rider to apply force at a larger radius from the center of the crank axle, resulting in higher torque and greater power output, making it easier to propel the bike forward, especially when climbing hills or riding at high speeds.
