A bicycle frame is the main structure of a bicycle, providing support and shape. It is typically made from materials like steel, aluminum, or carbon fiber, which offer a balance of strength and weight. The frame connects various components, including the wheels, handlebars, and seat, allowing the bicycle to function effectively. Frames come in different designs and sizes to accommodate various riding styles and body types. Common types include road bike frames, mountain bike frames, and hybrid bike frames. The geometry of the frame affects the bike's handling, comfort, and performance, making it an essential aspect of bicycle design.