Abstract: An air suspension system includes a plastic or metal piston fixed to the vehicle axle and an elastomeric bellows which is air tightly vulcanized from its lower open end to the upper part of the piston and from its upper open end to the metal plate fixed to the vehicle chassis to form a pressured air chamber and a single-piece bottom plate with bumper, which is completely made of reinforced plastic material. The air suspension system includes a compression part vulcanized to the elastomeric bellows and a bumper part absorbing the loads and which is mounted to the upper side of the piston after that it is vulcanized to the lower open end of the elastomeric bellows.