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Basic guide to towing

The National Caravan Council – in cooperation with the Caravan Club and the Camping and Caravanning Club – has published what is probably the most definitive guide to towing a caravan. Distilling the contents of that 32-page document, however, the following is a more basic guide.

Weight ratios

One of the most critical aspects of towing a caravan is getting right the weight ratio between the trailer and the car that is towing it.

This may be quite a challenging and complicated business, requiring a knowledge of some of the esoteric terms used by both car and caravan manufacturers.

The key terms are:

  • Gross Train Weight (GTW) – the maximum permitted weight as defined by the car manufacturer of the car and the caravan combined;
  • Maximum Permissible Towing Mass (MPTM) – again defined by the car manufacturer as the maximum weight of any trailer the car may tow;
  • Maximum Authorised Mass (MAM) – the weight of the car combined with the weight of is driver and passengers, luggage and the noseweight of the caravan it is towing:
  • Mass of vehicle in running order (MRO) – perhaps one of the most critical measurements, also known as the kerbside weight or kerbweight, which is the weight of the car as defined by the manufacturer;
  • caravan MRO – the caravan also has an MRO which is defined by the manufacturer and refers to the unladen weight of the trailer;
  • Maximum Technically Permissible Laden Mass (MTPLM) – is the maximum weight of the caravan and everything you pack within it, including water, gas cylinders, and personal kit, a total weight that must not be exceeded for legal use on the road.

Armed with this bewildering array of technical terms, it is possible to begin to match the caravan you want to tow to the car that is needed to tow it. The equation boils down to a ratio expressed by the fully laden weight of the caravan as a proportion of the kerbweight (MRO) of the car – in other words, the fully laden weight of the caravan times 100, divided by the car’s MRO.

It is generally recommended that this ratio should not be greater than 85% for someone learning to tow a caravan, up to 100% for the most experienced such drivers, and never in excess of 100%.

Getting these ratios right and ensuring that you do not exceed any of the weight limits is important for staying within the law and also helps determine what size car you need to tow the caravan.

Matching caravan to car – and vice versa – may therefore prove a mathematical headache. It might be welcome news, therefore, that the website WhatTowcar has a useful online calculator to help you make the right match.

Generally speaking, of course, the heavier the caravan you want to tow, the heavier and more powerful the car you need to tow it.


It is not only the laden weight of your caravan that matters, but also the way in which it is loaded. Heavy items need to be stowed on the floor, as closely as possible to the trailer’s axle and in a way that does not adversely affect the noseweight which the car is designed to bear.

Finally, when towing, don’t underestimate the importance of having the most appropriate mirrors. There are both safety and legal implications, so check out our Guide to Towing Caravan Mirrors for more information.