A continuously variable transmission comprising: a radially inner race, having a first radially inner race structure and a second radially inner race structure spaced along an axis wherein at least one of the first radially inner race structure or the second radially inner race structure is axially movable; a radially outer race, having a first radially outer race structure and a second radially outer race structure spaced along an axis wherein at least one of the first radially outer race structure or the second radially outer race structure 26(b) is axially movable; planetary members in rolling contact with the radially inner race and the radially outer race; an outer race assembly including: a hydraulic cavity housing; the first radially outer race structure fittingly engaged with the hydraulic cavity housing; a hydraulic cavity sealed between the hydraulic cavity housing and the first radially outer race structure to control axial movement of the first radially outer race structure as fitted in the hydraulic cavity housing, the hydraulic cavity permits axial movement of the first radially outer race structure with respect to the hydraulic cavity housing and to maintain the hydraulic cavity; characterized in that the first radially inner race structure is rotationally constrained with respect to the rotation of the second radially inner race structure via an extension engagement with the first radially inner race structure and the second radially inner race structure, wherein the first and second radially inner race structures (23a, 23b) have limited rotational displacement with respect to each other. a radially inner race, having a first radially inner race structure and a second radially inner race structure spaced along an axis wherein at least one of the first radially inner race structure or the second radially inner race structure is axially movable; a radially outer race, having a first radially outer race structure and a second radially outer race structure spaced along an axis wherein at least one of the first radially outer race structure or the second radially outer race structure 26(b) is axially movable; planetary members in rolling contact with the radially inner race and the radially outer race; an outer race assembly including: a hydraulic cavity housing; the first radially outer race structure fittingly engaged with the hydraulic cavity housing; a hydraulic cavity sealed between the hydraulic cavity housing and the first radially outer race structure to control axial movement of the first radially outer race structure as fitted in the hydraulic cavity housing, the hydraulic cavity permits axial movement of the first radially outer race structure with respect to the hydraulic cavity housing and to maintain the hydraulic cavity; characterized in that the first radially inner race structure is rotationally constrained with respect to the rotation of the second radially inner race structure via an extension engagement with the first radially inner race structure and the second radially inner race structure, wherein the first and second radially inner race structures (23a, 23b) have limited rotational displacement with respect to each other. a hydraulic cavity housing; the first radially outer race structure fittingly engaged with the hydraulic cavity housing; a hydraulic cavity sealed between the hydraulic cavity housing and the first radially outer race structure to control axial movement of the first radially outer race structure as fitted in the hydraulic cavity housing, the hydraulic cavity permits axial movement of the first radially outer race structure with respect to the hydraulic cavity housing and to maintain the hydraulic cavity; characterized in that the first radially inner race structure is rotationally constrained with respect to the rotation of the second radially inner race structure via an extension engagement with the first radially inner race structure and the second radially inner race structure, wherein the first and second radially inner race structures (23a, 23b) have limited rotational displacement with respect to each other.