Provided is a continuously variable transmission including a variable diameter first pulley assembly, a second pulley assembly, coupled with an endless power transfer element. The first pulley assembly includes: a first side member having a plurality of first guideways coupled to rotate on a first axle; a second side member having a plurality of a second guideways, separated from the first side member, coupled to rotate freely about the first axle; a plurality of pulley segments engaged with the endless power transfer element coupled with the first and second guideways arranged in the circle about the first axis of rotation; an actuator for rotating the first and second side member relative to each other about the first axis of rotation, producing radial displacement of the pulley segments and changing the effective diameter of the first pulley assembly; and a tensioner for tensioning the endless power transfer element.