A unidirectional rod sealing ring adapted for forming a sealed condition in association with a member such as a piston rod or shaft axially movable in a bore of a hydraulic cylinder, the sealing ring including an elastomeric ring member having an axially facing sealing face, an opposite axially facing pressure face, a circumferential radial outer surface, and a circumferential radial inner surface, the elastomeric ring member being cooperatively receivable in an annular groove around the bore of a hydraulic cylinder with the sealing face in position in opposed relation to a first axial groove wall, and the pressure face positioned in opposed relation to an opposite second groove wall, the sealing face including at least one continuous annular bead of relatively small radial extent positioned for sealably engaging the first axial groove wall, and the radial inner surface including an inner most circumferential lip of relatively small axial extent positioned for circumferential sealed engagement with the member axially movable in the bore.