Driving and operating 215Driving 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 than1300 kg the use of a stabiliser isstrongly recommended when drivingabove 50 mph.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 3 309.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 load applies upto the 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 281.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.The maximum permissible verticalcoupling load (75 kg) is specified onthe towing equipment identificationplate and in the vehicle documents.Always aim for the maximum load,especially in the case of heavytrailers. The vertical coupling loadshould never fall below 25 kg.
