A shock absorber for a vehicle may include a piston and a valve disc assembly. The piston defines a plurality of passages extending through the piston between an upper working chamber and a lower working chamber of a fluid chamber. The valve disc assembly engages the piston and controls a flow of fluid between the upper working chamber and the lower working chamber through the plurality of passages. The valve disc assembly includes a variable radius spring disc among a plurality of discs. The variable radius spring disc has a varying outer radius. The valve disc assembly has a stiffness that varies circumferentially based on the variable radius spring disc such that an actuation of the valve disc assembly with respect to the piston varies circumferentially.