In a transmission chain including alternately interleaved and articulably connected sets of link plates, the link plates of least one of the sets have back surfaces arranged for sliding contact with a chain guide. These back surfaces have a convex, substantially arc-shaped, curvature in the longitudinal direction of the chain, and a convex, substantially arc-shaped, curvature in the widthwise direction. The radius of curvature of the widthwise curve of the back surface of each of the link plates of the at least one set is at least as great as the radius of curvature of the curve of the same link plate in the longitudinal direction.