Towing capacity, weights and limits guide

Having one of the best tow cars is essential if you plan on regularly hauling a trailer or if you fancy the idea of a caravan holiday. However, there’s a limit to how much weight a vehicle can safely tow, so it’s important to understand towing weights and capacities before setting off with a trailer hooked up.

Car manufacturers will publish a specific towing capacity for most models they sell, informing the driver of the heaviest load that the car safely tow. Knowing this figure is crucial if you plan on towing – a car with a 1,000kg capacity will be fine for many small and mid-size trailers, though it will be wholly unsuitable if you need to haul a 1,500kg caravan.

It’s slightly more complex than just checking your car’s towing capacity and setting off. There are multiple weight figures to consider, as well as other factors such as road gradients and the weight distribution of whatever it is you’re towing.

Read on for our run-down of everything you need to know about towing weights and capacities.

What is a towing capacity?

A towing capacity is the heaviest load that a given car is able to tow. It will be quoted in kilograms (kg) and should never be exceeded. It is the combined weight of the trailer and any load it’s carrying.

A car manufacturer may not quote a figure for every car in its range (for example, city cars don’t usually have official towing capacities, due to the fact they aren’t especially powerful and are unlikely to be used for hauling cargo), though as a rule of thumb, most family-sized cars will typically have some towing credentials to their name.

When checking your car’s towing capacity, or researching the towing capacity of a car you plan to purchase, make sure the quoted figure is for your exact car model and engine combination. Towing capacities can vary between different versions of the same car depending on the engine size, fuel type, whether it has an automatic gearbox, or whether it has four-wheel drive.

If you’re looking to buy a car to use for towing, bear in mind that cars with powerful engines or four-wheel drive often have the highest tow capacities. This is just a general rule – a 300bhp Land Rover will certainly make a better tow car than a 700bhp Ferrari – so always check the quoted towing capacity.

No car will have a quoted towing capacity greater than 3,500kg. This is the maximum legal ‘braked’ towing capacity in the UK. For ‘unbraked’ trailers, this reduces to 750kg – but what’s the difference? 

What’s the difference between braked and unbraked towing capacity?

Car manufacturers will usually quote two figures for towing capacity: ‘braked’ weight and ‘unbraked’ weight. As their names imply, the former is for trailers, caravans, horseboxes etc that come with brakes that work in tandem with the car’s, whereas the latter is for unbraked loads where the car is solely responsible for the braking. 

Because a braked trailer is more controllable than an unbraked one, the maximum towing capacity for the latter will likely be much lower.

Your car’s unbraked and braked towing capacities are usually listed on your car’s VIN plate, typically located on most cars’ driver’s side door sill. You may also find your car’s towing capacities in the owner’s manual, and in the Practicality section of our reviews. If you’re still struggling to find the towing weights, your car’s manufacturer should be able to tell you what they are. If no figures are listed, it means the car isn’t deemed suitable for towing at all.

Maximum trailer lengths and widths

It’s not just payload capacities that you need to consider when towing a heavy load. There are also legal restrictions on the size of the trailer you’re allowed to tow with your car, regardless of whether the towing load itself complies with the limits.

The widest your trailer is legally allowed to be is 2.55 metres, with the maximum length of a trailer with a payload up to 3,500kg being seven metres. For the length restriction, this doesn’t include the trailer’s A-frame – this is a part at the front of the trailer with a shape that resembles a capital A when viewed from above, and is where the tow hitch is located.

Towing capacities on gradients

Because of the extra weight slung out the back, a car with a heavy towed payload can behave differently going up and down hill than it does on straight and level ground. All of that extra weight will blunt performance and make it harder to pull away from a standing start when you’re heading up an incline, and you’ll need to be wary of the payload affecting the controllability of your car when you’re driving back down.

As a rule of thumb, the maximum towing figures for a car will be valid for gradients of up to 12%, though this may vary depending on the manufacturer – check your car’s owner’s manual to see if this is the case for your car. If you can plot your route out beforehand, it may be worth trying to avoid steeper inclines and descents when you’re towing heavy loads – especially if they’re not far off your car’s maximum towing capacity.

Nose weights when towing

When you’re towing with your car, one weight you’ll need to consider is the ‘nose weight’. This isn’t to do with the front of your car; it instead dictates the load being applied on the tow bar when the car and trailer are stationary. The maximum nose weight varies from car to car, and the maximum nose weight should be listed in your car’s owner’s manual.

The nose weight of your trailer or caravan is important to bear in mind, as the amount of weight being forced down onto the tow bar can have an impact on your car’s handling. For example, too much weight will force the rear of the car down, which by extension lifts the front of the car up and affects your car’s steering. 

Conversely, too little weight over the tow bar could be an indication the weight balance of your towed load is too rear-biased. All that weight located out back will mean your car can become harder to control in crosswinds, and increase the chances of your trailer swinging from side-to-side (more commonly referred to as ‘snaking’).

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