Abstract: A printing cylinder assembly adapted to be removably supported on a hydraulically operable mandrel having means to hydraulically apply radially outward forces is disclosed. The printing cylinder assembly has a generally cylindrical coated printing cylinder having two open end portions, and a generally annular sleeve positioned within each end portion and in shrink fit relation therewith. Each annular sleeve has a generally annular groove therein and at a location which corresponds to the general location of application of the radially outward forces when the cylinder is positioned on the mandrel. Radially outward forces are hydraulically developed by the mandrels and are transmitted to the cylinder through the annular sleeves to retain the cylinder and the mandrel as an integral unit. The grooved portion of each annular sleeve defines two adjacent annular stepped portions wherein the grooved portion has a greater flexibility in the radial direction than the adjacent stepped portions.