Preparing a Vehicle for Towing

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.

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.

This 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.

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.

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.

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

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.

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.

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.

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.