A pulley device configured to support a belt of a chain tensioning idler or a runner roller includes a bearing having inner and outer rings and a pulley having at least one C-shaped pulley part mounted on the bearing outer ring with an inner cylindrical portion of the pulley part press-fitted on the bearing outer ring, the bearing outer ring having a material projection and the inner cylindrical portion of the pulley part having an axial groove configured to allow the material projection to slide axially through the groove when the pulley part is slid axially onto the outer ring, the material projection forming an axial stop for the pulley part when the pulley part is rotated relative to the bearing outer ring.