A flywheel (10) comprises pendulum masses (30) arranged circumferentially about the axis of the flywheel (10). Adjacent ends of each pendulum mass are pivotally connected to each other via links (32) pivotally mounted to pivot pins (42). The pendulum masses are tuned to vibrate at the order of vibration that requires suppression and the tuned frequency varies with the speed of the flywheel to eliminate the order of vibration over a broad range of engine speeds. The relative movement of the masses (30) acts to reduce the amplitude of torque pulse peaks and troughs enabling the performance of a flywheel of a given mass to be enhanced, particularly for an engine at idle speed.
