Tow Vehicle Setup

Everyone who intends to tow a caravan, or indeed any sort of trailer, needs to be aware that various tow vehicle and trailer combinations can behave in slightly different ways and certainly different from just driving the tow vehicle itself. In this comprehensive article, Malcolm Street looks at the major vehicle considerations plus the equipment you need when towing safely.

The Tow Vehicle

Modern vehicles, being either four wheel drive or two wheel drive (as in most sedans) make excellent towing vehicles. You may have heard a saying in the vehicle industry that "there's no such thing as a bad tow vehicle". This statement is generally correct, although the problems that can occur from time to time is a bad tow vehicle choice!

Caravanners need to be aware that various tow vehicle and caravan combinations can behave in slightly different ways and certainly different from just driving the tow vehicle itself. Today's caravans have all the creature comforts desired and those comforts all add weight, which does affect towing. To ensure safe journeys therefore, it is necessary to have a tow vehicle and caravan that are compatible and use the best towing equipment.

One of the most important aspects of ensuring total enjoyment of the caravanning lifestyle is having the right tow vehicle. Whilst this article title generally refers to choosing a new tow vehicle, it can apply equally to ensuring a vehicle already owned is suitable for the proposed towing task.

In days of yore, that is, before the Holden Kingswood, the only consideration with a tow vehicle was the size of the engine - basically the more "cubes" the better! However, with the advent of things like coil spring rear suspension, front wheel drive and monocoque vehicle structure, factors like the engineering strength of the rear end became equally important.

If purchasing a new vehicle, then give some thought to what is planned to be towed. Neither a 5.0 litre V8 sedan nor a Toyota Land Cruiser is needed in every towing situation but a tow vehicle that is working well within it's power and engineering limits is going to be a more comfortable drive, than one that is being worked hard. There are many other factors to consider before hastily choosing & setting up a tow vehicle, so it's a good idea to take your time and learn as much as you.

Towing Regulations

Prior to the end of 1998, there was some considerable confusion about this, as well as the fact that various states had different regulations. What was legal in one state wasn't in another. However, national regulations for vehicles with a Gross Vehicle Mass (GVM) of less than 4,500kg took effect in 1998 and accept that either the maximum capacity of the towing apparatus (ie tow bar or hitch) or the vehicle manufacturer's recommendations on maximum towing mass (ie fully loaded caravan) apply, which ever is the lesser. That applies because some tow vehicles can have various ratings of tow bar/hitch fitted.

The only exception to the above is where the vehicle manufacturer has not specified a maximum towing mass, the limit is stated to be 1.5 times the unladen or kerb mass of the motor vehicle if the trailer is fitted with brakes or the unloaded mass of the motor vehicle if the trailer is not fitted with brakes.

However, just about all vehicle manufacturers specify maximum towing mass these days and they also specify something else as well; maximum ball weight. That refers to the vertical load on the towball imposed by the caravan coupling. The ideal weight for this is considered to be about 10% of the fully loaded weight of the caravan and it's important to know that some vehicles, mostly those imported from Europe and Japan sometimes have a stated maximum ball weight considerably less than 10% of the maximum towing mass.

What this does in reality is reduce the recommended maximum towing mass, if you apply the 10% factor the other way. In the past this has caused some problems. A noted example was the Mitsubishi Pajero, a capable tow vehicle but restricted by a low maximum ball weight. Mitsubishi eventually did some "retro specifying", with several of their models, bringing the ball weight up to a much more respectable level.

It is also important to realise that some vehicle manufacturer's specifications can vary depending on road conditions or what is fitted to the vehicle. One particular 4WD manufacturer has different maximum towing weight for on-road or off-road. Another manufacturer's maximum ball weight specification can be affected by the type of tow bar or tow hitch that is fitted and also whether a load distribution hitch is used.

Sedan or Four Wheel Drive?

Because of the weight of some caravans, there's a perception that only 4WD's can be used for towing. However, this is not true at all. Four wheel drives are often only necessary for venturing off road or towing heavy trailers. As long as manufacturer's towing recommendations are not exceeded, modern 2WD sedan vehicles, including those with front wheel drive, are just as capable of towing a caravan or camper trailer as a four-wheel drive. Front wheel drive vehicles are often looked at with doubt but as long as a weight distribution system is used, there should not be problems.

To achieve maximum towing weight capabilities, some manufacturers require additional features like auto transmission coolers and suspension and brake modifications. When comparing vehicles, have a good look at the towing specifications - in addition to the above, some manufacturers have items like speed restrictions above certain weights.

If you do feel that a four wheel drive is the right choice for you then you'll quickly discover this is a large market that requires a different set of purchase criteria than with buying a sedan. It's wise to do your research before you head out to the car yards and its particularly important to understand which features makes one 4WD vehicle better for towing than another. Thankfully such answers are clarified in our range of 4WDing topics, in particular the following article...

Buying a 4WDThis article focuses on the major considerations when choosing a 4WD vehicle for the purpose of travelling and camping. We give some brief definations of the various terms used to categorise 4WDs, and discuss various features and their practicality in the outback. See Buying a 4WD.

Petrol or Diesel?

In some cases, like with many 2WD sedan vehicles, there isn't a choice but certainly with most 4WD vehicles there is and it's very much a case of personal preference. Petrol engines might have a slight performance edge but modern turbo diesel technology is very good and if long distances are planned, then there's no reason not to go for the oil burner.

Manual or Auto Gearbox?

Having a manual or auto gearbox is often a matter of personal preference but some vehicle manufacturers recommend an automatic transmission for towing larger trailers or caravans. One advantage is that the driver needs only to concentrate on the prevailing road conditions and not to worry about whether the vehicle is in the correct gear. With a manual gear box though, there is often one more gear, which does make uphill and undulating roads easier to negotiate. Reversing is much easier if the vehicle has an automatic transmission.


Generally the type of suspension on the towing vehicle is not important as long as it is firm. Leaf springs are often considered more capable of supporting loads than coil springs but a good load distribution hitch will counteract the tendency of the rear of the vehicle to sag. As long as the suspension system (including the shock absorbers) is in good condition, then suspension system modifications for towing a caravan are not usually necessary, unless specified by the vehicle manufacturer.

Self-levelling Suspension

Some tow vehicles are fitted with self-levelling suspension. If this is the case, then the manufacturer's recommendations in regard to hitching up a trailer must be followed. Unless the trailer is very small, a load distribution hitch is almost essential on these vehicles and failure to follow the recommendations could result in damage to the vehicle's suspension.

Related Articles - see Travelling with Trailers & Campers

Towbars and Hitch Receivers

There are two types of towbars generally available for towing vehicles. A light duty towbar is made for towing box trailers and boat trailers, whilst a heavier version, normally called a hitch receiver, is made for towing trailers and caravans up to the limit of the tow vehicle's capabilities. Whatever their capacity, all towbars/hitches should have a readily visible nameplate showing their towing capability.

Towbars are characterized by a ballmount of 20mm flat steel that is attached by two bolts to the towbar. Whereas, hitch receivers have a 50mm square steel tube ballmount that inserts into a similar sized socket and is fixed by a 19mm pin and circlip. This does have the distinct advantage of being easily removed when not required!

Towing Ball Height

One thing to check with a towbar/hitch is that the towing ball height and caravan coupling are roughly at corresponding heights, otherwise when coupled up, the caravan may ride with a nose up or down attitude.

Determining the correct ball height for a level caravan is done quite easily by measuring the distance from the ground to the bottom of the coupling on the front of the caravan drawbar. This should then be compared with the distance from the ground to the base of the tow ball on the rear of the vehicle. These measurements should be nearly the same. If this is not the case, the ball mount may need to be adjusted or altered.

Weight Distribution Equipment

When a caravan is coupled up, the rear of the tow vehicle usually drops and the front rises thus reducing stability and vehicle control. One of the most desirable features of towing is to get the tow vehicle and caravan back as level as possible. The most efficient (and safest) way to do this is to fit a weight distribution system.

Weight Distribution Bars

Also known as stabilisers, torsion, or level-rides have the effect of transferring weight from the rear wheels to the front of the tow vehicle, thus ensuring efficient steering and braking. The bars are fitted between the towbar/hitch and the drawbar of the caravan.

In a way it's a bit like have a big tension spring between the tow vehicle and caravan but can be thought of more easily if the weight distributing bars are compared to handles on a wheelbarrow. The higher the handles are lifted the more weight is moved onto the wheelbarrow wheel and the easier it becomes to hold it up. Similarly, the more tension that is placed on the weight distribution bars, the more weight is transferred forward onto the front wheels of the tow vehicle.

Caravan Electrics

Electric connection between the tow vehicle and caravan is usually achieved by a seven pin round or flat plug and socket but some vans with extra accessories, including battery charging capability, have a flat 12 pin plug.

Through the plug and socket run the connections for the running lights, stop lights, indicator, electric brakes and any other accessories. Wiring up an electrical socket on a tow vehicle is not difficult and is often done at the same time as the tow bar/hitch is installed.

Braking Systems

Most modern caravans have an electric braking system, which usually consists of drum brakes operated by electro magnets - a very small number of vans have disc brakes but they are not common. The electro magnets in the caravan brakes are activated by an electric brake controller fitted to the tow vehicle. It's necessary to have this otherwise the brakes cannot be activated and the tow vehicle manufacturer's maximum towing weight recommendation for an unbraked caravan is usually about 750kg!

Electric Brake Controllers

These are usually fitted somewhere close to the driver underneath the dashboard. They operate automatically being wired into the vehicle stoplights or can be activated manually by the driver, on a long downhill run. There are two varieties of brake controller, a solid state unit or a 'motion sensing' type. The latter with a pendulum motion, operates more efficiently and in proportion to the tow vehicle movements than does the solid state variety.

Electric brake controllers can be adjusted and once done correctly, the driver will be able to slow the tow vehicle and caravan combination just as smoothly as if the tow vehicle was by itself.

Breakaway Cable

For caravans over two tonnes, a breakaway cable is mandatory and should the van part company with the tow vehicle, then the van brakes are operated automatically.

Towing Mirrors

Something of a neglected item but still essential, extension mirrors should not be ignored. A driver should have a clear unobstructed rear vision, not just be able to see what is beside the tow vehicle and caravan. There are various types of towing mirrors. Some clip across the vehicle bonnet, some clip on to the existing exterior mirrors and some fit either mechanically or magnetically to the driver and passenger doors. The latter are the most expensive but also are the steadiest and give the best vision.


Even if you are not the mechanical type, it's worth having a few simple tools on board and easily accessible - screwdrivers of various sizes and types, pliers, multigrips and a shifting spanner or two - you never know when you might need them.

Setting Up and Driving Off

This is almost a subject in itself but if you have never towed before then it's worth hitching up your empty caravan and spending a few hours driving around getting used to the feel of towing. This can include time in an empty car park, practising reversing!

When a van is loaded it's also a good idea to check the ball weight because how the van is loaded will affect it. Ball weight is something to get right because if it is too light, the caravan will sway around, especially on long runs down hill. Alternatively, if the ball weight is too heavy, the tow vehicles rear suspension will be forced down, affecting braking, steering and in the case of front wheel drives, traction.

The easiest way is on a vehicle weighbridge. Weigh the fully loaded (including topped up water tanks) caravan by itself. It should be less than the Aggregate Trailer Mass (ATM) on the caravan nameplate. Hitch up the tow vehicle and weigh again with just the caravan wheels on the weighbridge. The difference between the two weights is the ball weight and it should be close to 10% of the fully loaded weight. If not, then something may have to be moved but if it's right then you are ready to leave.

Happy Caravanning!
Related Articles - see How to Tow a Trailer

Finally, if you have never tried the Caravan lifestyle, then do some research before buying anything. Websites like this one offer good advice and enable you to search for, and make contact, with manufacturers and retailers.

By using our Caravans Directory you will find websites and contact details for businesses Australia-wide.

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Created: July 2008
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