Philip Lord — 11 February 2016

Following on from last week’s article on the eight most common caravan myths, we thought we’d further burst the bubble on some misled claims.

1. Roof-mounted pressure vents don’t really keep out dust

This is a hotly-debated topic. For many van owners they are a thing of the past and just another leak waiting to happen. But, on the other hand, many happy vanners still swear by them. So, can they really keep out the dust?

When you hit the gravel track at speed with your pressure flap wide open, any positive pressure entering the van will assist in keeping the dust at bay, up to a point. All vans constructed with LP gas appliances have significant ventilation and dust will migrate into the van from these vents, whether a pressure flap is installed or not. On a given day and in the right conditions, they may help, as long as there are no other vehicles on the track to stir up the dust and that when it comes to stopping, you slow down progressively.

2. You need to accelerate to correct a swaying trailer

This is something that my father used to swear by, but when I remember back, it never ended well. Unless your van has electric brakes that allow you to take control to manually slow the trailer down (in which case, accelerating may actually assist in correcting the sway), the best thing is to take your foot off the accelerator and brake gently until the car and trailer combination have come to a complete stop.

Try to find the cause before moving off again. Common causes are an incorrectly loaded trailer or a flat tyre on the trailer.

3. You don’t need to travel with your water tanks full            

The water tanks in your caravan are generally centred around the axle/s and fitted underneath the van, so by travelling with them full, it lowers the centre of gravity of the van, making it safer to tow. Because the water tanks fitted to vans do not have baffles in them, if the tanks are only half-full, the water is free to move from side-to-side and may contribute to the sideways movement of the van.

4. Towing mirrors aren’t necessary if you have a camera

Towing mirrors are required in almost all cases when you tow a caravan. A camera is a great addition to any arsenal of towing equipment, but it should be used in addition to a good set of mirrors, not instead of. 

Next time you hook your van up to the car, drive in a straight line for about 30m, then stand at the back corner of the caravan and look down the side of the van toward the car. If you can’t see the entire mirror, then you will have reduced visibility to the rear when towing and you may be compromising your safety.

5. You should store your van with empty water tanks

It may not seem obvious at first thought, but by actually storing your van with the water tanks full, you will reduce the likelihood of mould, mildew and algae growing in the tank, especially if you drop in one or two Puritabs prior to storage.

Then, when you go to use the van, drain the water from the tanks and use it to water the lawn, then refill the tanks with fresh water ready for use.

6. You must slow down when being overtaken by a truck

When being overtaken by any large vehicle, the air that is displaced by that vehicle has the potential to upset the caravan. To reduce the likelihood of this happening, you should maintain your speed, which effectively stretches out the vehicle and van combination and keeps the van under more control.

If you feel you wish to exercise more control over the van, you could apply a small amount of braking force via the electronic brake controller’s manual override.

7. More can be carried on the drawbar if the weight is countered

This one is tricky because you can fit more stuff on the drawbar as long as it is within the caravan manufacturer’s specifications and the extra weight doesn’t exceed the towball capacity of the vehicle.

The problem comes when you try to counter the weight by placing items down the back of the van to compensate. This results in ‘yaw inertia’, where you have two weights separated by the length of the van, which act similarly to a pendulum, but on a horizontal plane. As the van travels along the road, these weights may gain sideways momentum and could eventually lead to uncontrollable trailer sway.

The way to reduce the likelihood of this happening is to centre the load around the axle/s.

8. European caravans don’t suit Australian conditions

This is a controversial issue, but also a misunderstood one. For instance, how are ‘Australian conditions’ actually defined? Does that mean standard highways and sealed country roads, or the road up to Cape York?

A look under many Australian-built caravans reveals a considerable amount of RHS steelwork, which is where much of the van’s strength lies and also, therefore, weight. Whereas, a British or European caravan might just have two main rails which includes the drawbar and not much else.

‘Not enough chassis strength’ is the obvious but incorrect conclusion. British and European caravans tend to have a more monocoque body structure, where much of the strength is built into the body, rather than the chassis, resulting in a lighter weight but strong caravan.

9. You don’t need to lower tyre pressures if you fit air suspension

Many people believe this, but it makes no difference. You should always lower your tyre pressures when travelling for any distance on unmade or corrugated roads.

There’s no set pressure, as it obviously relates to the weight of your caravan, the number, size and load rating of its tyres and the ambient temperature, but most experienced outback travellers suggest dropping them to 25-28psi. Just make sure you re-inflate them when you hit the bitumen again.

You need to think of your tyres as front-line shock absorbers. The harder they are, the less shock they absorb. Air suspension simply gives your caravan an easier ride on all surfaces, but even easier if you lower your tyre pressures.

10. You can load your tow car to its GVM and still tow your van

Not always. Some of the latest crop of vehicles with high tow ratings can actually tow very little when laden to, or near, their Gross Vehicle Mass (GVM).

For example, if you load Nissan’s new NP300 Navara with plenty of accessories, four large adults and a load full of chairs, folding tables, a barbecue and a few slabs of ‘sundowers’, it will reduce the permissible download on your towball considerably.

So do your homework and check the real towing specs of your tow tug before you hook it up to your large caravan. Pay particular attention to the vehicle’s Gross Combined Mass, which is the maximum allowed combined weight of vehicle and trailer, specified by the vehicle’s manufacturer.

11. You don’t need a WDH if your tow car has air suspension

Well, you might, or might not.

Land-Rover specifically advises against a WDH being used when towing with any of its models fitted with air suspension, as it conflicts with the system’s auto levelling system. However, Jeep says a WDH is required if towing a caravan weighing more than 2200kg (the approximate weight of a Grand Cherokee diesel) even if it is fitted with its optional Quadra-lift air suspension.

And even though it doesn’t offer an air suspension option, Kia does not recommend the use of load levelling devices on any of its vehicles fitted with a genuine Kia accessory towbar.

The problem here is that if you are involved in an accident with a WDH attached and your vehicle manufacturer has not approved the use of them, your insurance company could disown you.

The lesson: always check with your vehicle manufacturer before fitting a WDH.


caravan myths