Rear axle for a motor vehicle and method for manufacturing it

The suspension system, comprising two lengthwise arms (12) with wheel carriers (24), connected by a torsion cross-member (14), has each of the arms made at least partly from extruded metal or metal alloy, with the direction of extrusion lying perpendicular to the arm's lengthwise axis. Each arm is made up of a first profile (16) that is pivoted to the vehicle body and to which the cross-member is fixed, and a second profile (22) with the wheel carrier (24), attached to the first profile by a tenon and mortise joint.