A face gear set having a face gear and an original pinion. The original pinion may mesh with the face gear. The face gear set may have a new pinion, different from the original pinion, which meshes with the face gear in accordance with at least one design parameter different from a corresponding design parameter of the original pinion. The new pinion may have a tooth surface defined by a theoretical plane. The tooth surface of the new pinion may maintain tangency contact with the original pinion during rotation and translation of the plane over a meshing area of the original pinion with the face gear, and also during rotation of each of the face gear, the original pinion and the new pinion at constant speed about the new pinion's axis of rotation.