A gear has a gear body made of a first plastic material. The gear body has an axis of rotation, external toothing arranged around an axis of rotation, a centrally located receiving opening, and an intermediate portion located between the external toothing and the wall of the receiving opening. The gear body is fixedly integrally formed on a support body, which is arranged at least partially in the intermediate portion and is made of a second plastic material having a higher stiffness and lower elasticity than the first plastic material, such that surface portions of the external toothing, of the wall of the receiving opening, of the intermediate portion, and of the support body form a substantially flat end face of the gear. The external toothing is helical toothing with teeth which, at least in portions, extend at a helix angle to the axis of rotation.

A mechanism including a first pair of races having a first pair of raceways and a first rolling element operable to roll between the first pair of raceways, wherein at least one of the first pair of raceways has a substantially variable curvature along at least a portion of a path of the first rolling element. A program product that determines a solution by adjusting the curvature of a first pair of raceways on opposite sides of a rolling element, at least one of the first pair of raceways having a substantially variable curvature along the contact points in the direction of the corresponding range of motion for the rolling element.