Reciprocating motion can be converted to rotary motion through a crankshaft and a connecting rod. In a joint between a connecting rod and a piston, the connecting rod rocks with respect to the piston. In some situations, the connecting rod is a pullrod always in tension or a pushrod always in compression making it difficult to lubricate the bearing surfaces. A joint is disclosed in which the bearing surfaces rock with respect to each other with no sliding between the surfaces. The connecting rod has a bearing surface that is part of a cylinder having a radius equal to a distance between a central axis of the journal to which the connecting rod is coupled and the bearing surface. The pin has a convexly- or concavely-curved bearing surface and the local radius is based on material properties and the local peak force that the rocking joint is designed to transmit.