The A-Z Of Towing
Are you confused by the 85% rule? Do you mix up your MiRO and MTPLM? This A-Z of towing will put you straight. When you first start caravanning or towing a trailer, the jargon can be confusing. In this A-Z, we’ll explain some common towing terms – what they mean, and why they are important.
You’ve probably heard of the 85% rule. This is a guideline to make towing safer and more stable. When following the 85% rule, the loaded weight of the caravan should be no more than 85% of the kerbweight of the tow car. So, if your car has a kerbweight of 1,600kg then the caravan you tow behind it should weigh no more than 1,360kg (which is 85% of 1,600kg).
It’s not a legal requirement, but it is good advice for stable towing, especially for anyone who is new to caravanning.
The A-frame is the A-shaped front section of the caravan chassis, which extends beyond the caravan body. The jockey wheel is mounted to the A-frame, and so is the hitch which connects the caravan to the car.
Most modern cars have an electronic stability control system to help preventskidding. Think of AL-KO’s ATC as stability control for your caravan. Sensors monitor the caravan’s movements and apply the brakes if swaying or instability is detected.
This is the licence entitlement that permits a driver to tow a heavy trailer or caravan behind a car. The ‘B’ in ‘B+E’ is the standard car licence, the ‘E’ relates to towing a trailer.
If you passed your test before 19 January 2013, the B+E entitlement allows you to tow any trailer behind a vehicle weighing up to 3,500kg (Maximum Authorised Mass), provided the weight of the trailer does not exceed the vehicle’s towing capacity. If you passed on or after 19 January 2023, then you can tow a trailer with a Maximum Authorised Mass of up to 3,500kg, so long as this does not exceed the capacity of the towing vehicle.
It used to be the case that drivers who passed their driving test from 1 January 1997 onwards had to take a B+E test. Since 16 December 2021, the requirement to take a towing test has been withdrawn, meaning you can tow a trailer with a MAM of 3500 kg, so long as this does not exceed the towing capacity of the vehicle. Even so, we would strongly recommend having some instruction before towing a caravan or trailer for the first time!
Any car which has been approved for towing will have an official capacity for towing braked and unbraked trailers. The capacity for towing an unbraked trailer is typically around 750kg. The capacity for a braked trailer can be much higher.
A caravan is a type of braked trailer, so it’s the braked towing capacity which applies.
The breakaway cable is a secondary safety device that attaches between your caravan and your car while towing. If the caravan comes away from the car’s tow ball, the breakaway cable will pull tight. This applies the caravan’s brakes to slow it down, reducing the chance of a dangerous collision.
It’s an important safety feature and a legal requirement and should be used properly every time you tow. It is recommended to have a spare fast-fit breakaway cable in case of an incident.
The structural framework that supports the caravan is called the chassis. Most caravans in the UK are built on a chassis made by the German company, AL-KO.
Nobody is born knowing how to tow a caravan or trailer! The best way to learn is attending a towing course. We can show you how to tow safely on the road and will help you to master reversing. It’s not as tricky as you think! Find out more about our caravan courses!
The Gross Train Weight is the most your car and caravan combined are permitted to weigh. The GTW includes fuel, passengers, luggage, and so on. You should never exceed to the Gross Train Weight as you could risk the stability of the outfit and incur a fine.
The Gross Vehicle Weight (GVW) is the most your car is permitted to weigh once loaded up with people and their bags. Don’t drive your car overloaded, or you risk a fine.
Just like a car, a caravan has a handbrake. Pull the lever up to apply the handbrake, push it down to release it. For long-term parking, it’s good practice to chock the caravan’s wheels rather than relying on the handbrake to prevent the brakes from seizing.
The hitch is the component that connects the caravan to the car. It’s positioned at the front of the A-frame, and clamps around the tow ball for safe and secure towing.
Most hitches are fitted with a stabiliser to reduce unwanted movements while towing. A hitch-head stabiliser (also known as a stabiliser coupling) uses friction pads to resist unwanted movements. Your tow ball should be free from paint, grease and rust to ensure the stabiliser works as it should. A hitch-head stabiliser can make towing a caravan more stable and safer.
The jockey wheel is the small wheel secured to the A-frame. It supports the caravan when it is not attached to a car and allows the caravan to be manoeuvred manually or using a motor mover. The jockey wheel also allows the front of the caravan to be lifted and lowered for levelling and hitching.
This is the weight of a car including fluids, but with no passengers or luggage. A more precise definition is the weight of the vehicle with a 90% full fuel tank, all necessary fluids, and a 75kg allowance for the driver. This is the definition most car manufacturers use, although some don’t include the weight of the driver. It’s important to know the kerbweight as this is the best figure to use when checking your car and caravan are a suitable match for each other.
This is the caravan equivalent of kerbweight. The Mass in Running Order is the weight of the caravan ready to hit the road, but with no extra luggage or equipment inside. You may also hear the terms ‘ex-works weight’ or ‘unladen weight’, which essentially mean the same thing. Expect the MiRO to include the weight of a gas cylinder and liquids such as the toilet flush fluid. Although the MiRO should be accurate within a leeway of 5%, the most reliable way to know the exact weight of your caravan is to take it to a weighbridge.
Usually expressed as a percentage, this is the ratio between the tow car’s weight and the caravan’s weight. Typically, the kerbweight of the car would be compared with the caravan’s Maximum Technically Permissible Laden Mass (MTPLM). The lighter the caravan relative to the car the more stable car and caravan will be. So, all other things being equal, a car and caravan with a matching ratio of 60% should tow better than a car and caravan with a matching ratio of 80%. The Camping and Caravanning Club (along with other experts) advise that the matching ratio should not exceed 85% for anyone new to towing, although this makes a sensible guideline for all. Matching ratios of up to 100% are legal for experienced tow car drivers but never tow a caravan weighing more than the tow car – this risks instability and could contribute to a collision.
The MAM is the most a car or caravan is permitted to weigh when fully loaded. It means the same as the specific terms Gross Vehicle Weight (cars) and Maximum Technically Permissible Laden Mass (caravans).
This is the most a caravan should weigh when fully loaded. You should never exceed the MTPLM as you could jepodise the stability of your outfit and in servere cases, snap your caravan's axle. You can check that you haven’t overloaded the caravan at a weighbridge.
A motor mover makes it easy to manoeuvre your caravan. Rather than reversing onto a pitch with your car and caravan hitched together, you unhitch first and use the motor mover instead. The motor mover (usually a pair of electric motors which turn the caravan wheels via grippy rollers) moves the caravan into position, directed by a handheld remote control.
With the right training, you should feel confident in your reversing skills so that a motor-mover isn’t essential, but a motor mover makes for straightforward manoeuvring of your caravan at a campsite, on your driveway or in your storage yard.
The noseweight is the weight the caravan hitch applies to the tow ball. It is also referred to as the tow ball download. Your tow car will have a maximum noseweight which shouldn’t be exceeded. There will also be a maximum figure for the tow bar (if retrofitted) and the AL-KO stabiliser (100kg). For stable towing, aim for a noseweight of 5-7% of the loaded weight of your caravan, so long as this doesn’t exceed the permitted maximum for the tow ball or stabiliser. If you do not know the actual weight of your caravan, use the MTPLM figure in your calculations instead.
You should be able to buy a noseweight gauge from any good caravan accessory shop. As the name suggests, this is a gauge for checking the noseweight and is measured in kgs. To use the gauge, park your caravan on a level surface, put the handbrake on, and load the caravan as if you were going on holiday. Place the gauge under the hitch where the tow ball would fit if you were towing. Then wind the jockey wheel up so the weight of the caravan hitch is supported by the gauge. The reading will tell you the downward force being applied through the hitch, which you can compare with the maximum allowed.
Your caravan won’t go far without a car, and your holiday won’t be much fun with a car but no caravan to stay in. Together, your car and caravan combination are referred to as an ‘outfit’.
A caravan is a type of braked trailer, using overrun brakes. As the car slows down, the caravan’s hitch compresses. This in turn applies the overrun brakes, so that the caravan slows itself down rather than pushing up against the back of the car. Whenever you have reversed your caravan, pull forward as your last manoeuvre to reset the caravan brakes.
The payload is the difference between a caravan’s Mass in Running Order and Maximum Technically Permissible Laden Mass. This figure, usually given in kilos (kg), tells you how much weight in clothes, food, and camping equipment a caravan can carry.
Think of the swinging pendulum on an old grandfather clock. Now imagine looking down on a car and caravan from above, with the caravan as the weight at the end of the swinging pendulum. If the caravan moves to one side, the pendulum effect means it will then swing back the other way. Sensible speed and careful loading can minimise the pendulum effect while towing.
When hitching up car and caravan, it’s important to be 100% sure the two are safely and securely attached. To confirm the hitch head is securely gripping the tow ball, wind the jockey wheel so that it lifts the back of the car as well as the front of the caravan. Then you can be sure car and caravan are properly attached. Having performed the rewind check you can then stow the jockey wheel ready for towing.
This is the total length of your caravan, including the A-frame and hitch.
Snaking is when the pendulum effect gets out of hand. Usually, side to side movements from the caravan will ebb away without the driver doing anything. However, sometimes these movements become more pronounced and threaten to pull the car out of control. This is known as a ‘snake’ or ‘snaking’.
This may be caused by excessive speed for the conditions and is more likely on a windy day and when driving downhill.
Don’t panic if you find your caravan snaking. Keep the steering wheel pointing straight ahead and take your feet off the pedals. Resist the temptation to apply the brakes as this could make car and caravan jackknife. It will get worse before it gets better so trust the process! Be patient and allow the movements to subside as the car and caravan slows down. It may take a few seconds but the outfit should come back under control.
You can learn more about how to prevent a snake and what to do if one happens on a towing course.
A stabiliser is a device that helps keep the caravan under control by resisting any swaying or snaking motion. There are several different types of stabiliser, but the most common kind uses friction pads clamping to the tow ball to resist unwanted movements.
A tow ball is the round metal ball on the end of the tow bar to which the caravan hitch attaches.
The tow bar is the device which attaches to the car to allow it to pull a caravan or another kind of trailer. The tow ball sits on one end of the tow bar, while the other end is securely fitted to the car. Some tow bars are fixed in place, while others can be removed when not in use. There are also tow bars which drop down from under the car at the push of a button.
Caravans are generally wider than cars, which is why you should fit your car with towing mirrors. These attach to the wing mirror housing and give a much better field of vision than relying on the car’s mirrors.
In fact, you will almost certainly need to fit extension mirrors to stay the right side of the law. You must be able to see 20 metres behind you and 4 metres to the side. That just isn’t possible without towing mirrors. Without them you won’t be able to see down the sides of the caravan to make safe manoeuvres such as changing lanes on the motorway or reversing with precision down a country lane.
Caravans and other trailers need an electricity supply to power their lights and indicators. With a caravan, this electricity supply may also charge the leisure battery and power the fridge. The electricity comes from the towing socket. This is usually next to the tow bar. The 13-pin system has been used since 2008. Older caravans may use the 7-pin systems. Adapters are available if your car is 13-pin and your caravan 7-pin (and vice versa).
Some small trailers don’t have brakes. Cars have a different towing capacity for unbraked trailers compared with braked trailers such as caravans. The unbraked trailer capacity is usually much lower than the braked capacity.
This is the Vehicle Identification Number plate fitted to a car. As well as giving the VIN, these plates usually show four weights. The first two of the four are important to caravanners. The first figure tells you the Gross Vehicle Weight. The second gives the Gross Train Weight. The third and fourth figures are the axle weights. You must not exceed the Gross Train Weight when towing.
The caravan’s weight plate is a sticker or metal plate which displays the caravan’s weights. It will show the Mass in Running Order (MiRO) and the Maximum Technically Permissible Laden Mass (MTPLM). The difference between the two is the caravan’s payload. Some manufacturers add the tyre pressure and torque settings for the wheel nuts on the plate too. Unstanding what weights you must adhere to is essential for safe and stable towing.
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