The first thing to bear in mind is that the weight of whatever is towed must not exceed the maximum allowed by the vehicle manufacturer. This figure is usually given in the handbook or, failing that, may be expressed as a Gross Train Weight (GTW) on the VIN plate. The gross train weight is the maximum permissible combined weight of the towing vehicle and whatever it is towing. The towing limit can be calculated by deducting from it the Gross Vehicle Weight (GVW). This too should be stamped on the VIN plate. It should also be borne in mind that, for safety reasons, the weight of the trailer should ideally be no more than 85% of that of the tow vehicle and that it should never exceed 100%.

For motorhomes the next consideration is whether the converter permits the fitting of a towbar. Most do but it is worth checking. Another point is that living areas sometimes extend beyond the rear of the chassis making the fitting of a towbar impractical. Also if the motorhome is built on an AL-KO chassis (like many are) then drilling additional holes would invalidate the chassis’ warranty. Assuming any given motorhome is OK for towing a small car there are two principal ways of doing so. The first is to use an ‘A’ frame (sometimes referred to as a dolly,) the other is to use a trailer.

‘A’ frames are relatively small and light (typically 20kg) and can usually be folded up for storage. They are available for cars up to 1600kgs in weight – more than enough for most people. The frame attaches to a special bar that is permanently fixed to the front of the car by what is effectively a towing bracket in reverse.  At the other end of the ‘A’ frame the coupling head is identical to that on a caravan and is complete with an over-run damper, brake lever and breakaway cable. The brake lever normally operates the brake pedal of the car via a Bowden cable permanently attached to the pedal via a hole in the floor. Clearly, when being towed, the brakes will have no servo assistance so the force exerted by the brake cable needs to be relatively high for good braking.

Steering is achieved by releasing the car’s steering lock and using the natural castor action of the wheels to allow it to follow the motorhome. The car’s rear lights are wired to an under-bonnet socket where they can be connected to a 12N or similar socket on the back of the motorhome. If it is not possible to connect into the car’s wiring then a lighting board with triangles is attached to the rear of the car. A clip on number plate completes the formalities. The whole lot will cost around £750 for a DIY kit or £1000 fitted and ready to go.

Car a Tow 'A' frame- click for larger pic

Modifying the car in this way effectively turns it into a trailer in the eyes of the law.  European law on trailers lays down a number of stipulations. One of these is that any trailer built after April 1989, must have an auto-reverse brake mechanism. This is virtually impossible to achieve with an ‘A’ frame arrangement so it can be argued that such arrangements are not legal. This is the view taken by the National Trailer and Towing Association (NTTA) who also consider that the braking arrangement does not conform to the European Directive 71/320/EEC and subsequent amendments.

An alternative to the Bowden cable system is the use of a gadget known as a ‘Brake Buddy’.  This is a clever piece of kit from the USA that sits in the driver’s footwell of the towed vehicle. It uses inertia sensors to determine when the brakes of the towing vehicle have been applied and then applies force to the brake pedal of the vehicle being towed. The force is applied using compressed air from a compressor powered from the cigar lighter. The makers reckon it will work for up to 4 days before the battery of the vehicle being towed becomes flat. It beats drilling holes in the floor and is easy to transfer from vehicle to vehicle but what European law enforcement agencies might make of it remains to be seen.

Brake Buddy

On their website the NTTA says “A-frames may be offered with a braking system that applies the car's brakes. These do not conform to the law as the car then becomes a "braked trailer" and has to conform to European Directives contained within the Construction and Use Regulations. It does not conform to the European Directive 71/320/EEC and amendments regarding braking requirements in any way. The use of this A-frame for transportation is illegal. It is still OK for use to recover a vehicle to a place of safety.”

To get a better understanding of why the NTTA takes that view I spoke to their Executive Administrator, David Millington. He told me that there are three main areas of concern. The first is that cars towed with an ‘A’ frame can not be fitted with an auto-reverse brake mechanism. As mentioned above this is a clear legal requirement for any trailer built after April 1989.

The second is a concern that the performance of the braking system may not meet that required by law. Trailers since built since 1983 must have a brake efficiency of 45% and a parking brake capable of holding the laden trailer on an 18% gradient. These figures may be difficult to achieve consistently with an ‘A’ frame system.

The third reason is that modifying the towed car by fitting a towing frame may affect adversely its performance in a crash. This point in itself does not make a car illegal for towing but it does raise issues around type approval and insurance. Seemingly none of these points have yet been tested in a UK court of law and that has fuelled the belief by some that ‘A’ frames are legal for general towing. Indeed the use of ‘A’ frames does seem to be tolerated by the UK authorities. The Department for Transport is reported as saying that "when an A-frame is attached to a vehicle (e.g. a motor car) and towed by a motor vehicle (e.g. a motorhome) we believe the A-frame and car become a single unit and as such are classified in legislation as a trailer". "We believe the use of ‘A’ frames to tow cars behind other vehicles is legal provided the braking and lighting requirements are met". The key here is whether the braking requirements are met.

There are those who argue that ‘A’ frames are legal for general use in the UK and therefore, under the Vienna convention, they should be legal for UK outfits throughout Europe.  Try telling this to the French police when they stop you.  They’re much less forgiving than their UK counterparts. There are tales of fines, and even vehicle impoundment, in France, Spain and Germany. Of course some people will tell you that they’ve towed to Spain and back with an ‘A’ frame, without ever having being stopped, but I think they’ve just been lucky. To get round this some sellers of ‘A’ frames furnish buyers with a piece of paper stating, in several languages, that ‘A’ frames are legal in the UK and quoting the Vienna convention.

Other potential problems with ‘A’ frames include hitching and reversing.  Unlike a normal trailer it can be very difficult to get much side to side movement on the hitch head. This means that great care has to be taken when reversing the motorhome to line up accurately.

When reversing, there are two issues. The first is that the brakes will tend to go on. The second is that, in reverse, the natural castor action of the front wheels will tend to point them away from the direction of travel. The best advice seems to be to uncouple the car and reverse it independently.

This article would not be complete without a word on un-braked trailers. The laws say that trailers of up to 750kg (GVW) do not have to be fitted with brakes provided that they do not exceed half the kerbside weight of the towing vehicle. It’s not easy to find a car with a GVW less that 750kgs. Smart cars weigh less but have a GVW of more than 750kgs so they’re out. The French Aixam range however does fit the bill, weighing in at 675kgs maximum weight. What’s more they are available in the UK in right hand drive.  Is it therefore legal to tow one of these with an un-braked ‘A’ frame? The NTTA thinks so, according to its website.

Aixam Crossline

There is a counter view of the law that says if a trailer is fitted with brakes they must work regardless of weight. Cynics might say this has more to do with selling braked ‘A’ frames than an accurate interpretation of the law. I don’t know but, in circumstances like these, I’d always lean towards what the NTTA said.

If you do intend to tow a car with an ‘A’ frame check that your insurance covers you do so. Otherwise, in the event of an accident, your insurer may deem the outfit illegal and refuse to pay up. It may also be prudent to display an ‘On Tow’ sign

It’s also worth checking that the car you intend to tow is actually suitable for being towed. Most automatic cars and 4x4’s are not suitable for being flat towed (all wheels in contact with the road) but do check with the manufacturer as there are some exceptions.

One area where there is no dispute on the interpretation of the law is the use of trailers. Indeed, for continental travel the only sure solution from a legal point of view is to put the car on a suitable trailer. It’s a more costly alternative, and there is a weight penalty but, properly done, it does guarantee compliance with EU legislation. A single axle trailer capable of carrying loads of up to 1000kg will cost around £1,300 complete and weigh about 350kg. A tandem axle version capable of carrying loads up to 1500kg will cost around £1,600 and weigh 500kg.

Car trailers needn't be large

If budgets and weights allow it my advice would be to go for a four wheeled trailer as they are more stable when towing, especially bearing in mind the log rear overhang of some motorhomes. They are also much more stable if one wheel gets punctured. Of course arriving at a campsite with a motorhome, car and trailer may well attract additional fees, assuming they let you on in the first place!

Lastly a word on those devices (dollies) that tow by means of lifting the front or rear wheels onto a platform. Beware that such devices are definitely only legal for the recovery of broken down vehicles and may not be used for other purposes. Also strict speed limits apply.

For further information and advice try the following:

The National Trailer and Towing Association
The National Caravan Council
The Haynes Trailer Manual by Brian Bate
Towing Roadcraft - The essential towing handbook by Police Foundation author Philip Coyne