Bicycle wheels are circular components that allow a bike to roll smoothly. Each wheel consists of a rim, spokes, and a hub. The rim is the outer part that holds the tire, while the spokes connect the rim to the hub, which is the center of the wheel. The design of the wheel helps distribute weight and provides stability during rides. The size of bicycle wheels can vary, with common diameters being 26 inches, 27.5 inches, and 29 inches. Larger wheels, like 29-inch wheels, offer better rolling efficiency over obstacles, while smaller wheels, such as 26-inch wheels, can provide quicker acceleration and maneuverability.