Bicycle mechanics.

The first bicycles of the early nineteenth century were simple designs of wooden frames and metal hoops for wheels. Though these early bicycles were propelled by feet pushing along the ground, soon pedals were added to the front axle allowing the rider to drive the front wheel for locomotion. It was not until the late 1880s when the first chain-driven bicycle was introduced, thereby separating the axles from the primary point of locomotion and overcoming problems with handling, steering, and weight distribution. This explosive decade of development also saw the first pneumatic tires, gearing, and coaster brakes, the latter allowing the rider to brake by pedaling backwards. Another series of innovations a century later was spurred by an explosion in frame design and fabrication techniques including the use of better materials such as aluminum, titanium, and, eventually, carbon fiber.