Abstract: The shock absorber has a housing containing a damping chamber, a shock absorber piston mounted for movement in the chamber and an inertia operated damping control valve in the damping chamber for altering a damping factor of the piston movement in the chamber in response to a shock input or in response to an aceleration of the shock absorber. The damping chamber comprises a cylindrical housing and the inertia operated damping control valve comprises an orifice in the damping chamber housing, a pivotable valve member positioned to cover the orifice and a resilient member for biasing the movable valve member over the orifice. The damping chamber housing is oriented generally vertically and the resilient member is positioned between the cylindrical housing and the valve member.