A variable drive system for driving a needle bar (11, 11') of a tufting machine in a reciprocating motion, characterized by comprising: a pair of motors each connected to a drive shaft (41A, 41B); and a plurality of drive assemblies mounted in spaced series across the tufting machine frame, each drive assembly comprising: a pair of first drive members (55A, 55B) each linked to one of the drive shafts (41A, 41B) of one of the motors such that each of the first drive members (55A, 55B) is driven by operation of one of the motors; a pair of second drive members (60A, 60B)each linked to an associated one of the first drive members (55A, 5B) so as to be driven thereby; a pair of cam arms (65, 66), each cam arm having a proximal end coupled to one of the second drive members (60A, 60B) and a distal end spaced therefrom; a rocker arm extending between the cam arms (65, 66); and a push rod having a proximal end attached to the rocker arm at a location intermediate the ends (76, 77)of the rocker arm, the push rod linked to the needle bar (11, 11') of the tufting machine for moving the needle bar (11, 11') along a selected stroke; wherein as the motors drive the first drive members (55A, 55B), the cam arms (65, 66) are linearly moved in a substantially reciprocating motion for driving the push rods and the needle bar (11, 11') linked thereto along its stroke in a substantially reciprocating movement, and wherein the motors can be operated at different rates so as to correspondingly drive the linked or associated pairs of first and second drive members (55A, 55B, 60A, 60B) at different rates to vary the movement of each cam arm of each of the drive assemblies so as to adjust the stroke of the needle bar (11, 11'). a pair of motors each connected to a drive shaft (41A, 41B); and a plurality of drive assemblies mounted in spaced series across the tufting machine frame, each drive assembly comprising: a pair of first drive members (55A, 55B) each linked to one of the drive shafts (41A, 41B) of one of the motors such that each of the first drive members (55A, 55B) is driven by operation of one of the motors; a pair of second drive members (60A, 60B)each linked to an associated one of the first drive members (55A, 5B) so as to be driven thereby; a pair of cam arms (65, 66), each cam arm having a proximal end coupled to one of the second drive members (60A, 60B) and a distal end spaced therefrom; a rocker arm extending between the cam arms (65, 66); and a push rod having a proximal end attached to the rocker arm at a location intermediate the ends (76, 77)of the rocker arm, the push rod linked to the needle bar (11, 11') of the tufting machine for moving the needle bar (11, 11') along a selected stroke; wherein as the motors drive the first drive members (55A, 55B), the cam arms (65, 66) are linearly moved in a substantially reciprocating motion for driving the push rods and the needle bar (11, 11') linked thereto along its stroke in a substantially reciprocating movement, and wherein the motors can be operated at different rates so as to correspondingly drive the linked or associated pairs of first and second drive members (55A, 55B, 60A, 60B) at different rates to vary the movement of each cam arm of each of the drive assemblies so as to adjust the stroke of the needle bar (11, 11'). a pair of first drive members (55A, 55B) each linked to one of the drive shafts (41A, 41B) of one of the motors such that each of the first drive members (55A, 55B) is driven by operation of one of the motors; a pair of second drive members (60A, 60B)each linked to an associated one of the first drive members (55A, 5B) so as to be driven thereby; a pair of cam arms (65, 66), each cam arm having a proximal end coupled to one of the second drive members (60A, 60B) and a distal end spaced therefrom; a rocker arm extending between the cam arms (65, 66); and a push rod having a proximal end attached to the rocker arm at a location intermediate the ends (76, 77)of the rocker arm, the push rod linked to the needle bar (11, 11') of the tufting machine for moving the needle bar (11, 11') along a selected stroke; wherein as the motors drive the first drive members (55A, 55B), the cam arms (65, 66) are linearly moved in a substantially reciprocating motion for driving the push rods and the needle bar (11, 11') linked thereto along its stroke in a substantially reciprocating movement, and wherein the motors can be operated at different rates so as to correspondingly drive the linked or associated pairs of first and second drive members (55A, 55B, 60A, 60B) at different rates to vary the movement of each cam arm of each of the drive assemblies so as to adjust the stroke of the needle bar (11, 11').