The development of stronger materials and other technological and engineering advances made this possible. By the 1880s, the chain drive was commonplace. Gears allow the cyclist to pedal at a comfortable and efficient rate while traveling either uphill or downhill or with a headwind or a tailwind. On the old high-wheelers, the pedals were attached directly to the wheel. One turn of the pedals equaled one turn of the wheel.
Gears allows the cyclist to change that ratio.
A passionate advocate of cycling, he rode his first high-wheeler at the age of 28, and soon had sold his silk business and started a bike shop. A tireless inventor, he was convinced that geared bikes, then an oddity, were the future of cycling. Though existing gear-changers were awkward and unreliable, Velocio was undeterred. He spent much time inventing various gearing schemes. In 1905 he tested a two-speed derailleur called the Cyclist.