An actuator assembly comprising: a ballnut comprising a helical track; and a ballscrew (120, 220) comprising: a first translation bearing track disposed in a radially outward surface of the ballscrew, wherein the helical track and the first translation bearing track form a first translation bearing raceway in which a plurality of first translation bearing balls having a first diameter are disposed; and a second translation bearing track disposed in the radially outward surface of the ballscrew, wherein the helical track and the second translation bearing track form a second translation bearing raceway in which a plurality of second translation bearing balls having a second diameter are disposed; wherein the first diameter and the second diameter are not equal, characterized in that said actuator assembly further comprises an actuator drive unit ("ADU") housing comprising a first ADU track and a second ADU track; and the ballscrew (120, 220) further comprising: a first thrust bearing track disposed in a radially inward surface of ballscrew, wherein the first ADU track and the first thrust bearing track form a first thrust bearing raceway in which a plurality of first thrust bearing balls having a fourth diameter are disposed; and a second thrust bearing track disposed in the radially inward surface of ballscrew, wherein the second ADU track and the second thrust bearing track form a second thrust bearing raceway in which a plurality of second thrust bearing balls having a fifth diameter are disposed; wherein the fourth diameter and the fifth diameter are not equal. a ballnut comprising a helical track; and a ballscrew (120, 220) comprising: a first translation bearing track disposed in a radially outward surface of the ballscrew, wherein the helical track and the first translation bearing track form a first translation bearing raceway in which a plurality of first translation bearing balls having a first diameter are disposed; and a second translation bearing track disposed in the radially outward surface of the ballscrew, wherein the helical track and the second translation bearing track form a second translation bearing raceway in which a plurality of second translation bearing balls having a second diameter are disposed; wherein the first diameter and the second diameter are not equal, characterized in that said actuator assembly further comprises an actuator drive unit ("ADU") housing comprising a first ADU track and a second ADU track; and a first translation bearing track disposed in a radially outward surface of the ballscrew, wherein the helical track and the first translation bearing track form a first translation bearing raceway in which a plurality of first translation bearing balls having a first diameter are disposed; and a second translation bearing track disposed in the radially outward surface of the ballscrew, wherein the helical track and the second translation bearing track form a second translation bearing raceway in which a plurality of second translation bearing balls having a second diameter are disposed; wherein the first diameter and the second diameter are not equal, characterized in that said actuator assembly further comprises an actuator drive unit ("ADU") housing comprising a first ADU track and a second ADU track; and the ballscrew (120, 220) further comprising: a first thrust bearing track disposed in a radially inward surface of ballscrew, wherein the first ADU track and the first thrust bearing track form a first thrust bearing raceway in which a plurality of first thrust bearing balls having a fourth diameter are disposed; and a second thrust bearing track disposed in the radially inward surface of ballscrew, wherein the second ADU track and the second thrust bearing track form a second thrust bearing raceway in which a plurality of second thrust bearing balls having a fifth diameter are disposed; a first thrust bearing track disposed in a radially inward surface of ballscrew, wherein the first ADU track and the first thrust bearing track form a first thrust bearing raceway in which a plurality of first thrust bearing balls having a fourth diameter are disposed; and a second thrust bearing track disposed in the radially inward surface of ballscrew, wherein the second ADU track and the second thrust bearing track form a second thrust bearing raceway in which a plurality of second thrust bearing balls having a fifth diameter are disposed; wherein the fourth diameter and the fifth diameter are not equal.