Abstract: An automatic variable speed transmission, particularly for use in recreational vehicles, is disclosed. The transmission consists of a driving shaft and a driven shaft and a first centrifugal clutch hub rotatably carried by the driving shaft, and means are provided to rotate the first centrifugal clutch hub. A first centrifugal clutch assembly is secured to the first centrifugal clutch hub and is rotatable therewith, and a second centrifugal clutch hub is secured to the driving shaft and rotatable therewith and a first friction plate secured to the second centrifugal clutch hub is adapted to be engaged and driven by the first centrifugal clutch assembly upon the first centrifugal clutch assembly attaining a pre-selected speed of rotation. A driving shaft pinion is secured to the driving shaft and engages a first pinion of a first and second pinion group with rotatably carried by a gear casing and integral gear casing hub which is secured to the driven shaft.