Guidance

Tow a trailer with a car: safety checks

Checks you should carry out every time you tow a trailer, caravan or horsebox with a car, to make sure you're towing safely and legally.

The rules on what you can tow are different depending on when you passed your driving test.

Checks before you tow

Carry out the basic safety checks shown in this video to make sure that your vehicle and trailer are safe and legal.

Towing a trailer with a car: basic safety checks

You can be fined up to £2,500, be banned from driving, and get 3 penalty points for using a vehicle in a dangerous condition.

Tow ball and connections

Check that:

  • the trailer is correctly coupled to the towball or pin - follow the manufacturer’s advice
  • the coupling height is correct
  • the 7 or 13 core cable and plug isn’t damaged

Breakaway cable

Use a breakaway cable or secondary coupling. This engages the trailer’s brakes (if fitted) or stops the trailer if it becomes detached from the car.

Check that:

  • the cable isn’t worn or damaged
  • there’s enough slack in the cable so that it doesn’t accidentally apply the brakes
  • the cable won’t drag on the ground when you’re driving

Follow the manufacturer’s advice to make sure it’s connected correctly.

Wheels and tyres

Check that the tyres on both the car and trailer:

  • don’t have any cuts or bulges
  • are inflated to the manufacturer’s specification for the load being carried

Check that each tyre has a tread depth of at least 1.6mm:

  • across the central three-quarters of the breadth of the tread
  • around the entire circumference of the tyre

Check that the wheel nuts and bolts are tightened to the correct torque.

Check that mudguards are fitted to the trailer and they’re secure.

Lights and indicators

Check that there’s no damage to the lights, and that they’re all working correctly.

Load and weight limit

Check that:

  • the trailer isn’t overloaded
  • the load is distributed evenly
  • the load is secure

Find your car’s weight limit

The vehicle manufacturer’s plate gives information about weight limits for your car. Check the car’s handbook if a plate isn’t fitted.

Vehicle plate
An example of a vehicle manufacturer’s plate.
Weight Description
Weight 1 Maximum weight of the car on its own
Weight 2 Maximum weight of the car and trailer combined
Weight 3 Maximum weight for the front axle of the car
Weight 4 Maximum weight for the rear axle of the car

The maximum weight includes passengers, other loads, and fuel.

Trailer with no braking system

The loaded trailer:

  • must not weigh over 750kg
  • should not weigh more than 50% of your car’s weight

Trailer with braking system

The car and loaded trailer must not weigh over the second weight shown on the car manufacturer’s plates.

When you’re driving

You must not drive faster than the speed limit for the type of road.

If the trailer starts to snake or swerve, ease off the accelerator and reduce your speed gently. It’s a sign that either:

  • you’re going too fast
  • the trailer is loaded incorrectly

Don’t brake harshly on a bend, as it makes the trailer unstable. Reduce your speed in plenty of time when approaching any hazard.

Motorways

You must not drive in the right-hand lane of a motorway with 3 or more lanes.

More information

The National Trailer and Towing Association (NTTA) guide to safe and legal towing gives detailed information about:

  • attaching the trailer to the vehicle
  • driving with a trailer
  • maintaining a trailer

You can get a free safety check for a trailer up to 3,500kg through the NTTA’s free safety checks scheme. The check will highlight issues that you need to address.

You can also order ‘Trailer towing guidance and the law’ from the Society of Motor Manufacturers and Traders.

The Camping and Caravanning Club has a basic guide on how to tow a caravan.

Published 26 November 2016
Last updated 22 February 2018 + show all updates
  1. Added information about getting a free trailer safety check through the National Trailer and Towing Association's free safety check scheme.
  2. First published.