A connecting rod for a piston assembly includes first and second guidance members for guiding a piston assembly within a cylinder during piston stroke along a first axis. The guidance members are supported by first and second support ribs extending from a shaft of the connecting rod and include first and second sliding surfaces for contacting side walls of the cylinder. The connecting rod includes an attachment boss disposed at a first end of the shaft and defines a second axis perpendicular to the first axis. The first and second support ribs extend radially outwardly from the attachment boss and are spaced radially about the second axis by approximately 180 degrees.