Chapter 4 Tow Vehicles explains that almost any camper trailer under 1200 kg (2650 lb) laden can be towed (on-road) by a medium-sized car or SUV. Nevertheless, the heavier the tow vehicle and the lighter the trailer the better. The vehicle maker specifies the maximum towing weight. This is based on structural strength, tyre and axle loading and the ability to restart on a steep gradient etc. The vehicle maker also specifies the maximum tow ball weight.
The tow vehicle’s permissible laden weight includes the tow ball weight. It also includes everything carried and added on, and the weight of the driver and passenger/s. The latter is often misunderstood, resulting in many 4WDs being grossly overladen.
Chapter 4 Tow Vehicles – petrol/diesel
Petrol engine cars are quiet and flexible but may lack low-down pulling power (torque). Fuel consumption of older ones used to be about 35% higher than that of similar diesel vehicles, but is increasingly improving.
A petrol-engined vehicle’s fuel usage in soft sand may double or even triple. A diesel’s consumption in such use is often only 15% or so more than normal. Current vehicles are even more fuel miserly.
Diesel engined vehicles have strong pulling power. They cost more to buy and service but are great for towing, especially if travelling extensively off-road.
Diesel and petrol (less so Autogas) are readily obtained across most of Australia at no more than 375 km intervals. A few main roads in Western Australia have fuel at 450 km intervals. A comfortable range on-road is 600 km, but, for off-road use, 1000 km is preferable.
Chapter 4 Tow Vehicles – manual or automatic
Automatic transmission enhances control on soft sand and when edging over rocky surfaces. It does, however, limit engine braking (as does the lower compression of a petrol engine).
Chapter 4 Tow Vehicles – front/rear-wheel drive
Front-wheel drive is fine for towing light trailers on hard surfaces, but limits restarting on steep hills, particularly when wet. Rear-wheel drive is generally preferable. Long wheelbase 2WD utes seriously lack traction unless well laden.
Chapter 4 Tow Vehicles – four-wheel drive
A 4WD is desirable off the bitumen, not so much because it can drive all wheels but because 4WDs are usually more rugged and have greater ground clearance. A four-wheel drive’s most common use is to access sidetracks, but keeping 4WD engaged on dirt roads reduces tyre wear. It also eases engine loading on soft sand – often enabling the rig to be driven in a higher gear.
‘Soft’ 4WDs are fine for well maintained, short dirt tracks but most lack adequate ground clearance, underside protection and low range gearing. The more serious 4WDs have such ground clearance, protection and gearing – enabling them to drive slowly over rocks and in creek crossings. Such gearing may also be necessary to restart on steep hills whilst towing – and for driving on soft sand.
Think hard about all this before buying. With a trailer on tow, lack of low range gearing renders some trips impossible, or, if attempted, at risk of damaging the transmission.
Many 4WDs have a flaw that causes problems when bogged. It relates to their differentials (that big round bit in the centre of driven axles). A differential enables the outer wheels to turn faster than the inner wheels whilst cornering. This is necessary as the outer wheels follow a wider radius. Without that differential action, the vehicle will tend to plough straight ahead whilst cornering. Their downside is that they direct driving force to the wheel that has the least grip: a problem if bogged.
Some 4WDs have manual or automatic wheel hub mechanisms that partially or totally lock differential action. Most standard 4WDs however simply brake any wheel that loses traction. This is better than nothing, but differential hub locks are far superior.
If intending much off-road driving, at least have locking differential hubs at the rear. Without that, if one rear wheel and one front wheel spins, your ‘4WD’ becomes a zero wheel drive. There are many good after-market differential lockers. Most owners have them at the rear only but having one at the front too helps to extract a bogged rig, but the front one must never be engaged on its own as doing so renders steering close to unpredictable on even slightly slippery going.
The final vehicle choice
Service and repair shops exist in towns along the major part of Highway One (the road that runs all the way around Australia) is mostly close to the coast. There are very few facilities however on the Cape York Peninsula, nor in the northern part of Western Australia. Costs are high, especially in or near big mining towns such as Karratha, Newman and Port Hedland – but at least service there exists.
There are very few repair facilities in the outback. Bush mechanics are good at ‘fixing’ older vehicles but any with a computer-related fault can be a major problem in such vast and isolated areas. Some such vehicles have a ‘limp home mode’ but this usually limits power when you may seriously need it.
Outback retrieval can cost thousand of dollars – often for a trivial electrical fault (such as a non-working windscreen wiper but nevertheless linked to the computer) – that then partially or totally immobilises the vehicle. Because of this, many people who live in remote areas or travel extensively in such areas, have basic (often older) vehicles for which some service at least is available.
By far the most commonly-owned 4WDs of people living in the Kimberley are well looked after pre-computer Toyota Hiluxes, Troopies and Land Cruisers, and the 4.2 litre TD Nissan Patrols. Whilst low mileage examples are now few and far between (and costly) it may be well worth considering one in good condition if extensive outback travel is in mind.