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.