A roller circle assembly for heavy machinery includes an upper circular rail and a lower circular rail concentrically arranged about a central axis, and tapered rollers between the upper and lower rail. Each tapered roller includes a flange having an angled and convex flange contact surface that contacts the lower rail. The lower rail and/or the upper rail can include an angled surface configured for contact with the flange contact surface. The geometry of the rollers and the lower rail are configured to reduce the stresses applied to the rollers and lower rail due to contact between the flange contact surface and the angled surface.