Buying a caravan is exciting. Finding out it's too heavy for your tow car is not. This guide explains how to match a caravan to your car, and where the famous 85% rule fits in.
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Is the 85% rule law?
No. The 85% rule is guidance from the Caravan Club (now the Caravan and Motorhome Club), not a legal limit. It's about stability, not what the law allows.
The Caravan Club recommends that a beginner's caravan, fully laden, weighs no more than 85% of the car's kerbweight. Experienced towers might go up to 90%, and it says you should never exceed 100%.
The law is separate. Your legal limits come from your licence, the car's towing limit and gross train weight, and the caravan's MAM.
How the 85% rule works
Take your car's kerbweight (you'll also see it written as kerb weight) and multiply it by 0.85. The answer is the heaviest caravan the guideline suggests for a beginner.
The Caravan Club's own example: a car with a kerbweight of 1,750kg gives 1,487.5kg at 85% and 1,575kg at 90%.
For the caravan, use its MTPLM (maximum technically permissible laden mass). That's the heaviest the caravan is designed to be, with all your gear in. The Caravan Club bases its matching on the lightest the car can be and the heaviest the caravan can be.
Why it's a rule of thumb, not a guarantee
The Caravan Club says the link between weight ratio and stability comes from its own testing, member feedback and research. The heavier your car compared with the caravan, the more stable the whole outfit tends to be.
But it's not a guarantee. Loading, tyre pressures, weather, speed and your experience all matter. And a car can pass the 85% guideline and still be over its towing limit, or the other way round.
The numbers you need to match a caravan
- Car kerbweight: from the handbook or your VIN data.
- Car braked towing capacity: the caravan's MTPLM must not go over this.
- Gross train weight: car and caravan, both fully loaded, must stay within it.
- Noseweight / towball limit: the caravan's noseweight must be within the car's towball limit.
- Caravan MTPLM: from the caravan's plate.
- Your licence: see the licence rules.
Our towing capacity checker gives you the car-side numbers from your reg.
What is noseweight?
Noseweight is the downward force the caravan's drawbar puts on the car's towball. Too little and the caravan can snake. Too much and it can overload the back of the car and affect steering.
Your car's handbook gives a maximum towball (noseweight) limit, and the caravan's handbook will have recommended figures. Noseweight gauges are cheap and easy to use, so it's worth measuring rather than guessing.
Hybrids and electric cars
Some hybrids and electric cars have a low towing capacity even though they're heavy. If the car's towing limit is lower than 85% of its kerbweight, stick to the lower number. Always check the plate and handbook for the exact car.
Payload matters too
The caravan's MTPLM already includes what you load into it, but your car has a payload too. Passengers, luggage and the noseweight on the towball all count towards the car's own limits. If the car is packed full, you've got less room under the gross train weight for the caravan.
Choosing a tow car
Heavier cars generally make steadier tow cars. The Caravan Club's advice is that the car's kerbweight should at least match the caravan's laden weight and ideally exceed it. That doesn't mean you need a huge car. Plenty of owners match a mid-size car to a smaller caravan and tow happily at a ratio well under 85%.
Weigh it
The Camping and Caravanning Club suggests weighing your car and caravan in the state you'll tow them, using a portable weighing machine or a weighbridge. Your local Trading Standards office can point you to one.
Insurance and licence
Tell your insurer you're towing. The Camping and Caravanning Club says a towbar counts as a modification you should declare to your insurer. And check your licence: if you passed your test on or after 1 January 1997, you can tow a trailer up to 3,500kg MAM. If you passed earlier, you can usually drive a vehicle and trailer up to 8,250kg MAM.
A worked example (made-up numbers)
Say your car's kerbweight is 1,600kg. At 85% that's 1,360kg, so a beginner following the Caravan Club's advice would look for a caravan with an MTPLM of 1,360kg or less.
Now check the rest. If the car's braked towing limit is 1,500kg, the caravan is within it. If the gross train weight is 3,300kg and the car is loaded to 1,900kg, there's 1,400kg left, so the caravan fits there too. Last, check the noseweight against the towball limit.
These numbers are examples only, so use your own car's figures.
Common mistakes
- Using the empty caravan weight. Match against the MTPLM, because you'll load it up with gear.
- Treating 85% as the legal limit. It isn't. The law is about your licence, towing limit and gross train weight.
- Treating the towing limit as a green light. A car can be allowed to pull more than it can pull comfortably and stably.
- Forgetting the noseweight. It has to be within the car's towball limit.
- Not telling your insurer.
A quick checklist before you buy a caravan
- Look up your car's kerbweight, braked towing limit, gross train weight and towball limit.
- Ask the seller for the caravan's MTPLM and its plate details.
- Work out 85% of the kerbweight.
- Check the licence rules for you.
- Check the caravan fits within the width and length limits: 2.55 metres wide and 7 metres long if your car's MAM is 3,500kg or less, not including the A-frame (GOV.UK).
- Get insurance sorted.
Quick FAQs
Is the 85% rule law?
No. The 85% rule is Caravan Club guidance about stability. It suggests a beginner's caravan weighs no more than 85% of the car's kerb weight when fully laden, and the club says never to exceed 100%. The law looks at your licence, the car's towing limit and gross train weight, and the trailer's MAM.
Can my car tow a caravan?
It can if the caravan's laden weight is within your car's braked towing limit, the car and caravan together are within the gross train weight, the noseweight suits the towball limit, and your licence allows it. The Caravan Club also suggests keeping a beginner's caravan to 85% of the car's kerb weight.
What is gross train weight?
Gross train weight is the most that your fully loaded vehicle and fully loaded trailer can weigh together. It's on the VIN plate, and it must not be exceeded. If your VIN plate doesn't list a train weight, GOV.UK says you shouldn't use the vehicle for towing.
Not sure about your car's numbers? Check towing capacity by reg.