Towing with a Motorhome

Matching motorhome to 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.

Driving license issues

Drivers with a driving licence gained before 1 January 1997 are permitted to drive a motorhome without a trailer up to a maximum authorised mass (MAM) or gross vehicle weight (GVW) of 7,500kg. If towing a trailer the combined MAM of motorhome and trailer must not exceed 8,250kg. Thus a motorhome with a MAM of 7,500kg can only tow a trailer with a MAM of 750kg.

In practice most coachbuilt motorhomes have a MAM of about 3,000kg to 5,000kg so this driving licence tends not to be restrictive. If you drive a heavier motorhome and are limited in trailer weight you can consider a further DVLA test to widen your driving entitlements.

When such a driver reaches 70 his or her licence has to be renewed and unless a medical examination is taken the original entitlement is downgraded to leave just categories B and E. This means the driver is now limited to driving a vehicle with a MAM not exceeding 3,500kg, but because the category E remains any weight of trailer compatible with the towing vehicle can be towed.

The position changes dramatically for drivers who gained their licence after 1 January 1997 as their entitlement is simply a category B, which limits them to driving a vehicle with a MAM not exceeding 3,500kg and a maximum trailer weight of 750kg. A trailer in excess of 750kg is permitted if the combined MAM of trailer and motorhome does not exceed 3,500kg and the trailer M AM does not exceed the unladen weight of the towing vehicle. Thus a driver of a motorhome having a MAM of between 2,750kg and 3,500kg is only permitted to tow a trailer of up to 750kg. So in most cases motorhome drivers with a driving licence gained after 1 January 1997 will need to take the B+E driving test in order to tow a trailer with a MAM over 750kg.

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.

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, 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 trailering 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 be operative.

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 (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 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 figure you get when you subtract GVW from GTW 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. A lthough 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 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.

Definitions

  • Unladen WeightThe 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 LimitThe maximum permissible trailer weight quoted by the towing vehicle manufacturer (usually quoted for a vehicle when towing up a one in eight hill)