Figure 1: FE models of the four gear pairs analysed: (a) and (c) have an axisymmetric design for the lightweight gear, while 8 holes and 3 slots enable mass reduction in (b) and (d), respectively, with different degrees of discrete rotational symmetry. Gears (a) and (b) are designed to have the same total mass; the absence/presence of the holes cause different effect on blank stiffness; the same holds for gears (c) and (d).