Abstract: A multiple groove, variable pitch pulley comprises an annular hub threaded about its exterior surface. A stationary end flange is mounted at one end of the hub and a movable end flange is threaded onto the other end of the hub. One or more center flanges are threaded into the hub and lie between the stationary end flange and the movable end flange. The center flanges comprise a disk section and a collar section of lesser diameter than the disk section. The disk section of each center flange and the movable end flange each comprises an axial counterbore for receiving the collar section of an adjacent center flange.