Towing with a Motorhome
Data Sheet 25
For many campers a significant choice is whether to tow a caravan or drive a motorhome, but towing with a motorhome can often enhance the enjoyment of using your vehicle. While a VW campervan provides a terrific daytime base, for some its accommodation is too cramped for the evenings, but with a small caravan in tow you can be comfortable at the campsite while still enjoying the benefits of a daytime base anywhere. At the opposite end of the scale, a large motorhome is fine on the campsite but its size is limiting out and about. Tow a small car to the campsite and your daytime roaming knows no bounds. Alternatively if you wish to take a small boat or canoe on your travels a small trailer can make that possible.
So there are many good reasons to tow, but there are also some drawbacks concerning reversing, reduced speed limits and the detailed legal constraints of towing a trailer. This Data Sheet is intended to raise awareness of the issues involved in towing.
Left : A typical large motorhome towing a car on A frame
Matching motorhome and trailer
Matching a trailer to a motorhome is similar to that of car and caravan. You need to ensure you operate within the capability of the towing vehicle and the conditions of your driving licence. Details of such matching can be found on the Club’s Data Sheet 20 – Matching Car and Caravan.
You’ll find an explanation of the various vehicle weight terms used in the text in the definitions panel on at the bottom of this page. Please note also that the legal term for a motorhome is ‘motor caravan’, though we use the more commonly used term (motorhome) here.
Driving licence issues
Depending on when you passed your driving test different rules apply regarding your driving licence and Data Sheet 40 (Driving Licences) has further detailed information around these limitations.
Noseweight and towbars
Noseweight is a significant factor in towing stability and the National Caravan Council recommends a noseweight of about five to seven per cent of the weight of the loaded trailer. So a loaded trailer weighing 1,000kg should have a noseweight of not less than 50kg. The noseweight of the trailer applied on to the towball must also not exceed the motorhome manufacturer’s towball limit. It should be noted that the use of a chassis extension on a coachbuilt motorhome may reduce the permissible noseweight originally specified by the base vehicle manufacturer.
With a luggage trailer or caravan, noseweight can be adjusted to (or close to) the desirable weight by relocating kit fore or aft of the trailer axle. Where trailers are used to carry one large item such as a boat or car it is best to have a purpose-made trailer where the trailer axle is located to give a desirable noseweight with that fixed load.
Whatever you tow, whether a normal trailer or car using an A-frame, you will need to ensure you have a good towbar and towing electrical system fitted. If you have a relatively recent motorhome it is likely to have been the subject of European Type approval and as such must have a type-approved towbar fitted. Before buying a trailer check to confirm that a suitable towbar is available for your motorhome.
Sometimes there can be complications with underslung water tanks or other equipment impeding the satisfactory fitting of a towbar. A towbar fitter specialising in motorhomes is therefore recommended, especially where a chassis extension or towbar needs to be fabricated for the particular requirements of your motorhome.
Basic towing law issues
When towing you are automatically restricted to a maximum speed of 50mph on single carriageways and 60mph on dual carriageways and motorways, except where a lower general speed limit applies. Also you are not permitted in the outside lane of a motorway where there are three lanes or more.
The Road Vehicles (Construction and Use) Regulations limits you to towing an unbraked trailer with a MAM not exceeding 750kg or half the kerbweight of the towing vehicle, whichever is less. Where a trailer is fitted with brakes, even if the trailer does not exceed 750kg, those brakes must work properly.
Vehicle manufacturers also quote towing limits and these are normally given in the vehicle handbook. If only one towing limit is given assume it is for a braked trailer. The best way to check the braked trailer limit for a motorhome is to inspect the weight plate on the vehicle. The weight plate, which usually also carries the vehicle’s Vehicle Identification Number (VIN), is normally located under the bonnet or on one of the door pillars.
For coachbuilt motorhomes be sure to use the convertor’s plate as shown here (or AL-KO plate where the base vehicle rear chassis has been substituted with an AL-KO chassis) in case the original specified loadings as indicated on the base vehicle manufacturer’s plate have been amended. The top figure on the plate is the vehicle’s Gross Vehicle Weight (GVW) and the second figure down is the gross train weight (GTW). The GTW is the maximum combined weight of towing vehicle and trailer that is permitted. The difference between the GTW and GVW is your towing limit when the vehicle is fully loaded.
Do not be surprised if the towing limit given by the convertor is considerably less than the original base vehicle manufacturer’s limit. This can be a result of the convertor increasing the original GVW or the GTW can be reduced due to rear chassis extensions. Although these extensions are adequate for the habitation load, they often cannot sustain the same trailer load as the original short chassis. Sometimes the base vehicle’s original towing limit is reduced by half or more.
An unbraked trailer (right) must have a secondary coupling that will keep the trailer attached to the towing vehicle if the primary coupling fails.
Braked trailers up to 3,500kg must be fitted with a breakaway cable that will operate the trailer brakes if the primary coupling fails. Alternatively a braked trailer up to 1,500kg may have a secondary coupling (such as a strong chain) fitted.
Towing a car using an A-frame
The law when towing a traditional trailer is reasonably clear whether in the UK or Europe. But tow a car behind a motorhome on an A-frame and the situation is not so clear.
There has been some debate around Directive 71/320/EEC and UNECE Regulation 13 concerning braking system type-approval, however this only relates to new vehicles. Motor vehicles and trailers are within the scope of these technical regulations but A-frame devices are not.
The Department for transport (DfT) states “There is no harmonised EU legislation concerning the type-approval of A-frames and they cannot be considered as vehicles in the context of the legislation as they merely form a link between two vehicles”. However, for many years the DfT was clear that the use of devices such as A-frames, spectacle lifts and dollies were intended only for the purposes of recovery of broken down vehicles.
The current information sheet on this subject states: “We believe the A-frame and car become a single unit and as such are classified in legislation as a trailer.”and “We believe the use of A-frames to tow cars behind other vehicles is legal (in the UK) provided the braking and lighting requirements are met”. However on the Continent most countries still see it as a recovery tool and the DfT believes the Vienna Convention 1968 on Road Traffic cannot be used as a defence in disputes because the A-frame would not have been forseen at the time of the Convention.
Therefore the Club strongly advises you abide by the local laws for each country you travel through. In practice this means putting the car on a trailer.
A number of Club members towing with A-frames on the continent have been stopped by local police. In several cases in Spain, police officers have insisted on the decoupling of the A-frame and separate travelling, so be prepared for your partner or travelling companion to drive the car if requested.
Lighting is one issue that can be largely resolved by a connection to the motorhome electrics so all the car’s normal road lights function correctly. The regulations require a trailer to display two red triangular reflectors – which are often overlooked – and also to display the number plate of the towing vehicle.
Braking requirements are not so easy to comply with as many A-frame systems use a relatively simple overrun (also known as an inertia) braking system, as used on caravans, to operate the car’s brakes. The DfT comments on its sheet: “If the trailer braking system has power assistance it is likely that this assistance will be required while in motion to meet the required braking efficiencies.”
There are also concerns about the ability to reverse a car on an A-frame when using an inertia braking system. Traditional braked trailers can be reversed without problem because they have auto-reversing systems in the wheel hubs that enable the brakes to collapse when rearward motion is instigated. Cars do not have such systems. The DfT information sheet states: “From 1 October 1988 the inertia braking system was required to allow the trailer to be reversed by the towing vehicle without imposing a sustained drag and such devices used for this purpose must engage and disengage automatically. This will be very difficult to achieve on an A-frame using an inertia (overrun) device.” Some inertia-braked A-frame suppliers claim testing has proved their system meets the necessary braking force regulations and argue that cars on inertia-braked A-frames can be reversed without the need to manually operate any mechanism. One supplier says: “It takes a little skill, but with care, gentle reversing can be successfully achieved”.
In the past few years some A-frame suppliers have implemented designs to operate the car’s braking systems, including the power assistance system using electrical power from the towing motorhome. Suppliers claim these electrical systems provide the required braking efficiency and allow trouble-free reversing as the car’s braking operation depends on the motorhome’s brakes.
To avoid all the above technical problems relating to braking requirements, some campers have argued the braking requirements for A-frame towing of cars can be avoided by using a lightweight micro car where the GVW does not exceed 750kg. The argument goes that with a GVW (including A-frame) of less than 750kg, the unit can be considered as an unbraked trailer. However, if a braking system is fitted then the regulations require all the brakes to operate correctly and the micro car will have brakes.
While the DfT has set out its interpretation of the regulations, it has declared it is unable to give an authoritive interpretation of the law as this is a matter for the courts to decide. As far as the Club is aware, no one has yet been taken court in the UK for towing a car using a braked A-frame.
Above: Smart cars fitted with A-frames designed for use with braking systems.
Below: A-frame connectors being fitted to the front of a car to be towed. (courtesy Smart Tow)
As there is no mandatory testing regime in place, it is down to individual manufacturers to ensure their products meet the statutory requirements. If you decide to purchase an A-frame it would be wise to seek written assurance from your supplier that it complies with the regulations as laid out by the DfT.
If you do go down the A-frame route, check your car can be towed. Some cars, especially automatics, can have their transmission system damaged by being towed. Also inform your insurance company for both the car and your motorhome and check it is happy with the arrangements, especially if you intend to use the outfit outside the UK. And remember, reversing with a small towed trailer is notoriously difficult, especially when it is out of sight. Using a rear view camera can be helpful. Such cameras are now readily available as an aftermarket accessory.
- Unladen Weight The weight of a vehicle when not carrying a load and excluding fuel
- Kerbweight or Mass In Running Order (MIRO) This is defined in European Directive 95/48/EC as “the mass of the vehicle with bodywork in running order (including coolant, oils fuel, tools spare wheel and driver)”
- Maximum Authorised Mass (MAM), Maximum Gross Weight (MGW) or Gross Vehicle Weight (GVW) The maximum a vehicle or trailer is allowed to weigh when fully loaded
- Gross Train Weight (GTW) The maximum allowed combined weight of towing vehicle and trailer permitted
- Towing Limit The maximum permissible trailer weight quoted by the towing vehicle manufacturer (usually quoted for a vehicle when towing up a one in eight hill)
Further information and contacts
- To view or download the PDF version of this data sheet (25) click here.
- Department for Transport information sheet, ‘A Frames and Dollies’ can be found by searching on the Gov.uk website
Specialist motorhome towbars
Please note inclusion on these pages does not constitute endorsement by The Camping and Caravanning Club.