The invention relates to a tensioning device for use in vehicle power steering assembly, in particular, having a drive unit for rotating an input pulley rotatably connected to an output pulley via a flexible belt. The tensioning device includes a housing and an arm movably attached relative to the housing. A contact device is mounted on the arm and is adapted to be engaged with a portion of the belt between the input and output pulleys. The arm is movable relative to the belt to position the contact device against the belt to provide tension on the belt.