A hydraulic shimmy damper including: - a hollow body having an inner cylindrical surface and two end walls (13,14) defining an inner functional volume; - a piston having a piston head sealingly engaging said inner cylindrical surface so as to define two hydraulic active chambers (C1,C2) within the functional volume, said piston having a rod projecting from said piston head which sealingly traverses one of said end walls; - biasing means (16,17,18,19) to bias said piston relative to said body towards a rest position so as to allow for fore and aft motion of the piston around said rest position under action of external forces; - a hydraulic compensator having an internal fluid volume that is greater than a fluid volume expelled from the body when the piston moves fore and aft; - a hydraulic manifold arranged between said body and said hydraulic compensator and defining a transfer channel between said chambers that is connected to said hydraulic compensator, said manifold further receiving interchangeable hydraulic cartridge-type valves (CV1,RV1;CV2,RV2) for metering the fluid flowing from said chambers to said transfer channel, and allowing the fluid to freely enter said chambers from said transfer channel; characterized in that the biasing means further include: - a plunger projecting from another of said end walls for sealingly engaging an internal cylindrical surface of said piston, said plunger having a circumferential protrusion; - a spring carrier sealingly sliding around said plunger, said circumferential protrusion of said plunger forming a stop for said spring carrier and said piston; - first spring means extending between said body and said piston to urge said piston towards said spring carrier; - second spring means extending between said body and said spring carrier to urge said spring carrier towards said stop; said first and second spring means (18,19) being so adapted as to bias said piston towards said rest position in which said spring carrier abuts against said stop and said piston abuts against said spring carrier. - a hollow body having an inner cylindrical surface and two end walls (13,14) defining an inner functional volume; - a piston having a piston head sealingly engaging said inner cylindrical surface so as to define two hydraulic active chambers (C1,C2) within the functional volume, said piston having a rod projecting from said piston head which sealingly traverses one of said end walls; - biasing means (16,17,18,19) to bias said piston relative to said body towards a rest position so as to allow for fore and aft motion of the piston around said rest position under action of external forces; - a hydraulic compensator having an internal fluid volume that is greater than a fluid volume expelled from the body when the piston moves fore and aft; - a hydraulic manifold arranged between said body and said hydraulic compensator and defining a transfer channel between said chambers that is connected to said hydraulic compensator, said manifold further receiving interchangeable hydraulic cartridge-type valves (CV1,RV1;CV2,RV2) for metering the fluid flowing from said chambers to said transfer channel, and allowing the fluid to freely enter said chambers from said transfer channel; characterized in that the biasing means further include: - a plunger projecting from another of said end walls for sealingly engaging an internal cylindrical surface of said piston, said plunger having a circumferential protrusion; - a spring carrier sealingly sliding around said plunger, said circumferential protrusion of said plunger forming a stop for said spring carrier and said piston; - first spring means extending between said body and said piston to urge said piston towards said spring carrier; - second spring means extending between said body and said spring carrier to urge said spring carrier towards said stop; - a plunger projecting from another of said end walls for sealingly engaging an internal cylindrical surface of said piston, said plunger having a circumferential protrusion; - a spring carrier sealingly sliding around said plunger, said circumferential protrusion of said plunger forming a stop for said spring carrier and said piston; - first spring means extending between said body and said piston to urge said piston towards said spring carrier; - second spring means extending between said body and said spring carrier to urge said spring carrier towards said stop;