The Zenith motorcycle brand, produced in England from 1903 to 1950, was a Birmingham-based manufacturer known for innovative engineering and a wide range of motorcycles built with proprietary and proprietary-supplied engines. Founded by Frederick Barnes, Zenith became widely recognized for its patented Gradua variable transmission system, which offered improved flexibility and performance over conventional drivetrains. The company produced machines powered by engines from suppliers such as JAP, Villiers, Blackburne, and Bradshaw, covering everything from lightweight commuter bikes to large V-twin touring models. Zenith motorcycles were characterized by technical innovation, versatility, and strong performance, securing the marque a notable place in early British motorcycling history.