The key slewing parts of Most traditional beam transport trailers are traditional slewing ring products. Compared with the slewing drive, since the slewing ring has no out pack housing and its tarnish resistance are not very ideal, besides, the rotating range of tyres are also quietly limited since the turning system are pushed by hydraulic jack. While choosing the slewing dive as slewing part, the tarnish resistance of are not only improved, and also the turning angel of every tyre can be increased