A rotor module for an axial flux electric machine includes a back iron segment configured for attachment to a rotor base and a plurality of permanent magnets attached to the back iron segment. The back iron segment has a length less than a circumference of the rotor base. Each permanent magnet attached to the back iron segment has an opposite magnetic pole orientation from each adjacent permanent magnet attached to the back iron segment. A plurality of rotor modules is coupled to the rotor base to form a rotor for the axial flux electric machine.