Trailer safety checks before you tow

Published 10 October 2026. Every figure was checked at its source that day.

The short version

Check the coupling, the breakaway cable, the tyres, the lights and the load every time.
Tyre tread must be at least 1.6mm deep on the car and the trailer.
A trailer with no brakes must not weigh over 750kg loaded.
If the trailer snakes, ease off the accelerator. Do not brake harshly.

GOV.UK lists the checks to make each time you tow a trailer with a car. They are set out below in the order you would walk round the trailer.

Tow ball and connections

The trailer is correctly coupled to the tow ball or pin, following the manufacturer's advice.
The coupling height is correct.
The 7 or 13 core cable and its plug are undamaged.

Breakaway cable

Use a breakaway cable or secondary coupling. If the trailer comes off the car, it applies the trailer's brakes where fitted, or stops the trailer.

The cable is not worn or damaged.
It has enough slack that it will not apply the brakes by accident.
It will not drag on the ground.
It is connected as the manufacturer advises.

Wheels and tyres

Tyres on the car and the trailer have no cuts or bulges.
They are inflated to the manufacturer's figure for the load.
Tread is at least 1.6mm deep across the central three-quarters of the tyre's width, all the way round.
Wheel nuts and bolts are tightened to the correct torque.
The trailer's mudguards are fitted and secure.

Lights and indicators

Check that none is damaged and that every one works.

Load and weight

The trailer must not be overloaded. The load should be evenly spread and secure. How to load a trailer.

The car's manufacturer plate lists up to four weights. The first is the most the car can weigh alone. The second is the most the car and trailer can weigh together. The third and fourth are the limits for the front and rear axles. Each maximum includes passengers, other loads and fuel.

A trailer with no brakes must not weigh over 750kg loaded, and should not weigh more than half the weight of the car.
With a braked trailer, the car and loaded trailer together must not weigh more than the second weight on the plate.

What to do if the trailer snakes

Ease off the accelerator and let the speed drop gently. GOV.UK says snaking or swerving means you are going too fast or the trailer is loaded wrongly.

Do not brake harshly on a bend.
Slow down in good time for any hazard.
Do not use the right-hand lane of a motorway with three or more lanes.

For licence, size and speed limits, read the UK towing rules.

Sources, read on 10 October 2026

GOV.UK: tow a trailer with a car, safety checks