GORV - Digital Magazine Issue #25 | Page 35

RV FEATURE By and large (and as long as sensibly laden) a tow vehicle pulling an equally sensibly laden caravan that is no heavier than that tow vehicle is unlikely to be unstable — but never risk towing above 100 km/h as associated forces then truly escalate. There is a good case for using AL-KO or Dexter electronic stability control, but only to safeguard an already stable rig. Both companies responsibly state their product “cannot overcome the laws of physics”. TYRE PRESSSURES SUMMING UP A major and widely overlooked factor in tow vehicle stability is its rear tyre pressure when towing. When a caravan is hitched up, its (essential) nose mass pushes down hard on the towbar. That, like pushing down on the handles of a wheelbarrow, increases the load on the tow vehicle’s rear tyres. That in turn increases their tendency toward oversteer. It is essential to run those tow vehicle rear tyres at a pressure that reflects that added load. This will typically be from 7-10 psi (50-70 kPa) higher. Never increase front pressure — reducing by 2-3 psi (15-21 kPa) actually assists while towing. In some cases, using correct tyre pressures alone can transform handling. Caravan and tow vehicle stability is a far more complex issue than at first it appears. This, The ratio of hitch overhang to the wheelbase of the tow vehicle is important. / 35