A motorized roller shade is provided. The motorized roller shade includes a shade tube in which a motor unit, a controller unit and a power supply unit are disposed. The controller unit includes a controller to control the motor. The power supply unit includes at least one bearing rotatably coupled to a support shaft. The motor unit includes at least one bearing, rotatably coupled to another support shaft, a DC gear motor and a counterbalancing device. The output shaft of the DC gear motor is coupled to the support shaft such that the output shaft and the support shaft do not rotate when the support shaft is attached to a mounting bracket