A shock absorber for a vehicle is disclosed which has a pressure tube defining a fluid chamber, a piston rod, and a piston disposed within the fluid chamber, and carried on the piston rod, which divides the fluid chamber into upper and lower working chambers, and which has a plurality of passages extending between the upper and lower working chambers. A valve disc assembly controls a flow of fluid, and includes a spring disc. The spring disc has a non-symmetrical circumferential shape which enables a stiffness of the valve disc assembly to be tailored so that it begins to open at a first peripheral point, and continuously gradually opens about a non-symmetrical circumferential path until reaching a second peripheral point adjacent the first peripheral point.