Chassis frame variable interface

consist commercial vehicle, which by cross-members (17) with interconnected longitudinal members of the chassis of at least two modular side rail portions (1; 1 '; 2; 2'). The ends (43; 47) of the longitudinal carrier sections (1; 1 '; 2; 2') by a connecting shoe (3; 3 '; 4, 4') connected to each other. The connecting shoe (3; 3 '; 4, 4') is characterized in that the longitudinal support sections (1; 1 '; 2; 2') are arranged at a different height level and the connecting shoe (3; 3 '; 4, 4 '), the height difference between the (to be joined together ends 43; 47) of the sections (1; 1'; bridged 2 '), 2.