In some embodiments, systems and methods are described for a gear contact system configured to support radial, thrust, and moment loads, the system comprising a first gear comprising a first roller having a first roller bearing surface, the first roller bearing surface having a convex curvature defined by a first radius of curvature; and a second gear comprising a second roller having a second roller bearing surface, the second roller bearing surface having a concave curvature defined by a second radius of curvature.