Chainrings are the circular gears attached to the crankset of a bicycle. They work in conjunction with the chain to transfer power from the rider's legs to the rear wheel. Chainrings come in various sizes, affecting the bike's gear ratio and how easy or hard it is to pedal. Typically, bicycles have one, two, or three chainrings, known as single, double, or triple setups. A larger chainring allows for higher speeds on flat terrain, while a smaller one makes climbing hills easier. The choice of chainring size can significantly influence a cyclist's performance and riding experience.