Roof racks, caravan and trailer towin g 157Coupling so cket loadThe c oupling socket load is the loadexerted by the carav an / tra iler on thecoupling ball. It can b e varied by changingthe w eight distribution when loa ding thecarava n / trailer.The ma ximum permissible coup ling socketload for the towing vehicle (80 k g) is statedon the towing equipment id entific ationplate and should always be aimed for,particularly in the ca se of heavy caravans /trailers. The coup ling socket load shouldnev er be below 25 k g.When mea suring the coup ling socket load,mak e sure that the drawbar of the loa dedcarava n / trailer is at the sa me height as itwill be when the caravan / trailer is c oupledwith the towing v ehicle loa ded. This isparticularly imp ortant for carav ans /trailers with tandem axle.Rear axle load during towingWhen the carav an / trailer is coup led a ndthe towing vehic le fully loaded (includingall occupants), the perm issible rear ax leloa d must not be exceeded.National regulations regarding m aximumspeeds for vehicles towing a ca ra van /tra iler must be observed .Picture no: 17213T.tifTyre inflation pressureIncrease the ty re p ressure on the towingvehicle to the value specified for full load(see page 207). Also check the pressure ofthe caravan / trailer ty res.
