 It was in its turn superseded in 1924 by a four-cylinder 1074 cc Rover 9.The car, designed by Edmund Woodward Lewis (1870-1941) who had joined Rover from Daimler, had an unusual structure.Instead of the conventional chassis, the car had a backbone structure, formed by the engine crankcase, the gearbox housing, a rigid tubular propellor shaft housing, and the rear axle housing; the whole described as having a box girder section.