Roller bearings and chain incorporating the roller bearings

A roller chain comprising a plurality of sprocket-engaging rollers and a plurality of bushings, each bushing being surrounded by, and in coaxial, spaced, relationship with, one of said sprocket-engaging rollers about an axis of rotation, wherein each said sprocket-engaging roller has first and second ends and functions as an outer ring of a roller bearing, and each said bushing functions as an inner ring of a roller bearing, each said roller bearing comprising a plurality of bearing rollers disposed between its outer ring and its inner ring, each bearing roller being cylindrical, having first and second ends, and having a uniform diameter substantially from its first end to its second end, said diameter being equal to the spacing between said inner and outer rings, first and second substantially ring-shaped retainers disposed at the first and second ends of the outer ring respectively, each said retainer being unitary and at least one of the retainers comprising a recess having an axial interior wall and a radial interior wall, the radial wall facing, and being in engagement with, one of the ends of each of said bearing rollers and limiting axial movement of said bearing rollers, and a plurality of pockets formed on said radial interior wall, each said pocket receiving one of said ends of one of the bearing rollers and preventing relative circumferential movement if said parts of the bearing rollers around said axis of rotation.