A pulley is provided with first and second disks each having an outer surface and an inner surface, and a center hole with a center axis. Each disk has a hub formed at its center hole that extends outwardly from the disk outer surface. The inner side of each disk has a drive surface and a connection surface extending around its respective center hole. The connection surface is perpendicular to the center axis and the drive surface is angled relative to the connection surface to form the outer surface of each disk with a generally concave shape. The connection surfaces of the first and second disks are abutted and secured together using a fastening mechanism. The disks are arranged where the drive surfaces form an annular groove around the hubs and the hubs of each disk are aligned concentrically with the groove.