Abstract: A tire testing machine for measuring rolling resistance of a pneumatic tire by bringing a freely rotatably mounted tire into contact with a driven rotating load wheel. Spindles of the tire mounting structure and load wheel are supported in bearing assemblies. Each of the bearing assemblies includes an inner race rotatable with the spindle and an outer race mounted on a cylindrical sleeve. The sleeves are rotatably supported by an outer bearing assembly within a stationary housing. The speed of the sleeve and correspondingly the speed of the outer race is "slaved" to the speed of the associated spindle and inner race by drive motors whereby no relative motion exists between the bearing races and intervening bearing elements thereby negating bearing friction and associated losses. Elimination of bearing losses enables a more accurate and constant rolling resistance to be measured by the tire test machine.