Abstract: Improved semi-trailer which mainly consists of a chassis (14) with at least two supporting longitudinal runners (15), connected to each other by means of cross connections (16-17-18), and two or several single or double wheels (4) carrying the chassis (14), characterised in that the longitudinal runners (15) are situated on the side edges of the chassis (14) at a distance form each other which is larger than the distance between the wheels (4), and whereby every wheel (4) is fixed independently of the other wheels (4) on the chassis (14) by means of two parallel supporting arms (32, 33) which can hinge at their far ends.