The National Motor Museum Trust

Zenith, which began business in 1904, was widely known from 1909 for its Gradua gear. The system comprised a hand control which brought the engine-pulley flanges closer together or wider apart (to increase or decrease the effective diameter, thus raising or lowering the gear ratio) and moved the rear wheel to retain correct belt tension. Most machines had JAP engines but Fafnir, Bradshaw and Green units were also used. The engine of this exhibit was a water-cooled Green.