A drive clutch for a continuously variable transmission comprising: an input shaft adapted to engage with an engine drive component, the input shaft having a rotational axis; a support housing disposed about a portion of the input shaft such that the support housing is rotatable relative to the input shaft, the support housing having a central axis coincident with the rotational axis of the input shaft; a first sheave disposed about and engaged with a portion of the support shaft so that the first sheave rotates in combination with the support shaft, the first sheave having a rotational axis coincident with the rotational axis of the input shaft, the first sheave having a belt-engaging surface formed on a portion of one face; a second sheave disposed about the support shaft and mounted so as to be axially movable relative to the first sheave, the second sheave having a belt-engaging surface formed on a portion of one face which faces the belt-engaging surface of the first sheave, the belt-engaging surfaces defining a groove for receiving a belt that is adapted to engage a driven clutch; the first and second sheaves (16, 20) and the support housing defining a sheave assembly; a bearing assembly located between the input shaft and the sheave assembly to permit rotation of input shaft relative to the sheave assembly, a first centrifugal clutch assembly disposed about the input shaft, the first centrifugal clutch assembly adapted to provide controlled engagement between the first sheave and the input shaft, the first centrifugal clutch assembly including a clutch hub mounted to the input shaft, an engagement surface formed on or attached to the first sheave, and characterized by means engaging the clutch hub to the engagement surface upon the input shaft rotating at a speed relative to the sheave assembly that is above a threshold value, wherein the means engaging the clutch hub to the engagement surface includes a plurality of shoes and springs disposed on the clutch hub, the shoes being radially displaceable in response to rotational motion of the clutch hub, the springs biasing the shoes radially toward the input shaft, and wherein the engagement surface is a drum surface mounted or formed within a recess in a rear face of the first sheave; and an axial control mechanism mounted on the input shaft adjacent to the second sheave, the axial control mechanism controlling the movement of the second sheave toward and away from the first sheave as a function of the speed of the input shaft, wherein the second sheave is mounted so as to be separately rotatable from the axial control mechanism until the input shaft rotates above a threshold RPM. an input shaft adapted to engage with an engine drive component, the input shaft having a rotational axis; a support housing disposed about a portion of the input shaft such that the support housing is rotatable relative to the input shaft, the support housing having a central axis coincident with the rotational axis of the input shaft; a first sheave disposed about and engaged with a portion of the support shaft so that the first sheave rotates in combination with the support shaft, the first sheave having a rotational axis coincident with the rotational axis of the input shaft, the first sheave having a belt-engaging surface formed on a portion of one face; a second sheave disposed about the support shaft and mounted so as to be axially movable relative to the first sheave, the second sheave having a belt-engaging surface formed on a portion of one face which faces the belt-engaging surface of the first sheave, the belt-engaging surfaces defining a groove for receiving a belt that is adapted to engage a driven clutch; the first and second sheaves (16, 20) and the support housing defining a sheave assembly; a bearing assembly located between the input shaft and the sheave assembly to permit rotation of input shaft relative to the sheave assembly, a first centrifugal clutch assembly disposed about the input shaft, the first centrifugal clutch assembly adapted to provide controlled engagement between the first sheave and the input shaft, the first centrifugal clutch assembly including a clutch hub mounted to the input shaft, an engagement surface formed on or attached to the first sheave, and characterized by means engaging the clutch hub to the engagement surface upon the input shaft rotating at a speed relative to the sheave assembly that is above a threshold value, wherein the means engaging the clutch hub to the engagement surface includes a plurality of shoes and springs disposed on the clutch hub, the shoes being radially displaceable in response to rotational motion of the clutch hub, the springs biasing the shoes radially toward the input shaft, and wherein the engagement surface is a drum surface mounted or formed within a recess in a rear face of the first sheave; and an axial control mechanism mounted on the input shaft adjacent to the second sheave, the axial control mechanism controlling the movement of the second sheave toward and away from the first sheave as a function of the speed of the input shaft, wherein the second sheave is mounted so as to be separately rotatable from the axial control mechanism until the input shaft rotates above a threshold RPM.