A multi-disk refiner utilizing a plurality of spaced rotor disks which rotate in a housing in spaced relation to a plurality of spaced stator disks, the confronting disks having ribs thereon which abrade a stock suspension passing in the space between the rotor and stator disks. In accordance with the present invention, there is provided a plurality of flexible rotors which have spokes extending therefrom, the spokes being received in slots in loosely fitting relation so as to permit relative sliding movement between the spokes and the rotor disks while transmitting torque. A resilient bumper is provided on each of the spokes to provide a pivot point within the slot such that axial movement of the rotor disks provides a simple bending load to each spoke thereby defining a soft, linear spring system.