Preparing a Vehicle for Towing

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 herb 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.

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.

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.