The 85% guideline
Caravan and towing organisations recommend that a caravan's laden weight should be no more than 85% of the car's kerb weight, especially for less experienced drivers. It is a guideline for stability, not a law. Experienced drivers may go up to 100%, but should never exceed the car's legal towing limit.
Match ratio = caravan laden weight ÷ car kerb weight × 100
The legal limits
- The car's maximum towing weight (V5C section O.1 for braked trailers) must never be exceeded.
- The train weight, the car and trailer together, must be within the car's gross train weight.
- Driving licence: a full car licence lets you tow a trailer up to 3,500kg maximum authorised mass (category BE). Drivers who passed before 1 January 1997 can usually drive a car and trailer up to 8,250kg combined.
- Speed: 50mph on single carriageways and 60mph on dual carriageways and motorways when towing. Towing vehicles may not use the outside lane of a motorway with three or more lanes.
Noseweight
Noseweight is the downward force the trailer hitch puts on the towbar. Too little makes the outfit unstable and prone to snaking. Too much overloads the car's rear axle. A common guide is about 7% of the trailer's weight, up to the lower of the car's and the towbar's limits. Measure it with a noseweight gauge or bathroom scales and a piece of wood at the correct hitch height.
Sources
Rates and rules last checked 15 October 2026. These figures are a guide. For a decision that matters, confirm with the official source.