Zenith Motorcycles was a British motorcycle manufacturer established in Finsbury Park, London in 1904. Zenith motorcycles used engines from various suppliers, including Precision, Villiers and JAP. Under chief engineer Frederic "Freddy" Barnes, Zenith developed the "Gradua" gear, a variable pulley which adjusted the length of the drive belt by sliding the rear wheel backwards or forwards in the slots. This gave Zenith a great advantage which competitors claimed was unfair and many clubs banned the Gradua Zeniths, who simply then included the word "Barred" in their badge (see examle above).