In a planetary mechanical variator, the gear ratio is shifted by tilting the axes of spheres in a continuous fashion to provide different contact radii which, in turn, drive input and output discs. This system has multiple ‘planets’ in order to transfer torque. It allows for an approximate 5:1 speed variation via a simple adjustment handle. The main construction and functional features that render it so versatile include the integral motor flange of the housing, and the completely modular structure for the output flange and foot mounting. These features mean that the overall dimensions of the final drive can be reduced.