Abstract: A belt-type speed change device having a pair of pulleys around which passes a belt. A side plate of each of the pulleys is axially movable relative to the other, fixed, side plate, thereby to provide for changes in transmission ratio. A rest position of the movable side plate of one of the pulleys, in embodiments described the driven pulley, is defined by a first abutment. The first abutment is movable between an operative position in which it is engageable by the movable side plate to define the rest position of the movable side plate and a retracted position in which the first abutment permits further axial movement of the movable side plate away from the fixed side plate to a retracted position as defined by a second or stop abutment, thereby to permit removal of the belt from the pulleys.