Abstract: A twin mass flywheel comprising two co-axially arranged flywheel masses which are mounted for limited angular rotation in a drive and over-run direction relative to each other, and a plurality of pivotal linkages. Each pivotal linkage comprises a first link pivotally connected to one of the flywheel masses, a second link pivotally connected to the other of the flywheel masses and a pivot pivotally connecting the first and second links. The action of the links controls relative rotation of the flywheel masses, and the controlling action of the links is supplemented by one or more assister springs which operate over a significant proportion of the full drive direction range of relative rotation. The twin mass flywheel may further include end stops to positively limit relative rotation of the flywheel masses in the drive and over-run directions and may additionally include end stop resilient means which cushion the relative rotation of the flywheel masses just prior to contact of the end stops.