Piston ring, in particular for a piston of a vibration damper

A piston assembly for a vibration damper, said piston assembly comprising a piston and a piston ring, said piston comprising an upper side, a lower side, and a circumferential surface between said upper side and said lower side, said piston ring comprising

• a circumferentially extending radially inward facing covering surface covering said circumferential surface of said piston, said covering surface having opposed ends,
• a pair of parallel radially inward extending supporting segments on the radially inward facing covering surface of said piston ring, said supporting segments having respective axially facing retaining surfaces engaging respective said upper and lower sides of said piston,
• a tongue formed at one of said ends of said covering surface, said tongue having a pair of circumferentially and radially inward extending retaining segments which engage respective said upper and lower sides of said piston, and
• a cutout formed at the other of said ends of said covering surface, said tongue engaging in said cutout to form a butt joint.