Driving and operating 137TowingGeneral informationOnly use towing equipment that hasbeen approved for your vehicle.Entrust retrofitting of towingequipment to a workshop. It may benecessary to make changes thataffect the cooling system, heatshields or other equipment.Fitting of towing equipment couldcover the opening of the towing eye.If this is the case use the coupling ballbar for towing. Always keep thecoupling ball bar in the vehicle.Driving characteristics andtowing tipsBefore attaching a trailer, lubricatethe coupling ball. However, do not doso if a stabiliser, which acts on thecoupling ball, is being used to reducesnaking movements.For trailers with low driving stabilityand caravan trailers with a permittedgross vehicle weight of more than1000 kg a speed of 50 mph must notbe exceeded; the use of a stabiliser isrecommended.If the trailer starts snaking, drive moreslowly, do not attempt to correct thesteering and brake sharply ifnecessary.When driving downhill, drive in thesame gear as if driving uphill anddrive at a similar speed.Adjust tyre pressure to the valuespecified for full load 3 212.Trailer towingTrailer loadsThe permissible trailer loads arevehicle and engine-dependentmaximum values which must not beexceeded. The actual trailer load isthe difference between the actualgross weight of the trailer and theactual coupling socket load with thetrailer coupled.The permissible trailer loads arespecified in the vehicle documents. Ingeneral, they are valid for gradientsup to max. 12 %The permitted trailer loads apply up tothe specified incline and up to analtitude of 1000 metres above sealevel. Since engine power decreasesas altitude increases due to the airbecoming thinner, therefore reducingclimbing ability, the permissible grosstrain weight also decreases by 10 %for every 1000 metres of additionalaltitude. The gross train weight doesnot have to be reduced when drivingon roads with slight inclines (less than8 %, e.g. motorways).The permissible gross train weightmust not be exceeded. This weight isspecified on the identification plate3 190.Vertical coupling loadThe vertical coupling load is the loadexerted by the trailer on the couplingball. It can be varied by changing theweight distribution when loading thetrailer.
