A variable speed transmission including a housing, a frusto-conical gear having a hollow extending longitudinally through the gear and a plurality of spaced teeth on an inner and/or outer surface thereof. The plurality of spaced apart teeth include alternately teeth having a first addendum and teeth having a second or larger addendum. The transmission also includes a power shaft and a plurality of sliding face gears adapted to engage an input gear from an engine and a drive gear for engaging the frusto-conical gear.