The weight relationship between tow car and caravan is important for safe towing. To avoid the caravan outweighing the car, it is important that the towing car is as heavy as possible. If it’s not, the towing car is unlikely to be able to control a caravan should it become unstable when impacted by external forces such as a cross wind, heavy cornering or driving with too high speeds.
The 85% Rule
The ‘85% rule’ is not legislated, but a recommendation that states that the weight of the loaded caravan should be no more than 85% of the cars kerbweight.
Note: Keep the caravan as light as possible – the lower the weight, the better the match and, provided items are stowed properly, the safer it is to tow.
Towing weight and width limits
Most cars have a maximum weight they can tow. It’s usually listed in the handbook or specification sheet.
Alternatively the vehicle’s ‘gross train weight’ may be listed on the vehicle identification number (VIN) plate on the car. This is normally under the bonnet or inside the driver’s door.
The gross train weight is the weight of the fully-loaded car plus fully-loaded trailer and must not be exceeded.
If your plate doesn’t list a train weight, you should not use your vehicle for towing.
Width and length
The maximum trailer width for any towing vehicle is 2.55 metres.
The maximum length for a trailer towed by a vehicle weighing up to 3,500kg is 7 metres. This length does not include the A-frame.
The rules are different if you’re using a larger vehicle to tow a car, eg a motorhome towing a car.
Essential towbar tips
Always clean your towball before attaching a tow-hitch to it. Grease, paint, rust or other contaminants on the ball will contaminate the friction pads in modern caravan stabilisers, preventing them from working properly.
Use some emery cloth or wire wool to clean your towball back to bare metal, before attaching the stabiliser.
Check that your reversing sensors will not be affected by the new towbar, before it is fitted. Budget towbar systems are less likely to take account of reversing sensors, which can cause problems later.
When reversing your caravan onto a pitch, remember to pull forward by about a foot before uncoupling your car and caravan. This will release any compression in the hitch head ram, otherwise the head may shoot forward when lifted off the towball and might damage your bumper.