A piston damper assembly (10) includes a piston damper (12) and a relative velocity sensor (14). The piston damper includes a damper body (16), a piston rod (18), and a dust tube (20) which is attached to the piston rod. The relative velocity sensor incudes an axially extending first magnet (24) supported by the dust tube, a flux collector (28), and a first sensor coil (30). The flux collector is supported by the dust tube, includes an axially-extending first prong (34) in axially-extending proximity with the first magnet, includes an axially-extending second prong (36), and includes a joining member (38) connecting the first and second prongs. The first sensor coil surrounds the joining member and/or one of the first and second prongs. A piston-damper dust tube subassembly (42) includes the dust tube and the relative velocity sensor.