Roof box or trailer: what to choose?

If you are travelling with your family or need to transport bulky equipment, the boot of your car may be too small. So you've probably already asked yourself this question: is it better to buy a trailer or a roof box? ViaMichelin takes a look at the two options in detail.
Roof box or trailer: what to choose?

Spotlight on roof boxes

Roof boxes come in flexible and rigid versions, which attach to the roof bars. They are useful for carrying extra luggage, Christmas presents, camping equipment, etc. There are four main types:

  • soft cases, usually made of waterproof fabric;
  • compact models, which can hold a large sports bag;
  • mixed cases, in which you can put a suitcase inside;
  • long models, ideal for pushchairs, skis or surfboards.

The available volume ranges from 240 to 600 litres.

Advantages of a roof box

  • price, with entry-level models available for less than 100 euros;
  • ease of use, as no special requirements are needed to install a roof box;
  • increased fuel consumption of about 15% on the motorway, compared to roughly half that of a trailer.

Disadvantages of a roof box

  • limited maximum weight (75 kg);
  • limited load volume;
  • fairly high wind resistance.

What are the guidelines for driving with a roof box?

As with any accessory added to your vehicle, fitting a roof box requires you to take a few precautions, including:

  • reduce your speed and increase your safety distance;
  • be aware of vehicle height restrictions;
  • watch out for the wind.

Focus on trailers

A trailer can is designed to carry large loads when coupled to and towed by your vehicle. There are various models and sizes available that you can buy for just over £400 or cheaper if you rent, some of which can even be fitted with roof racks to carry bikes or motorbikes.

The advantages of a trailer

  • a large load capacity -up to 1,280 kg for larger models;
  • versatile uses (travel, removal, gardening, DIY, etc.);
  • long service life, even when transporting heavy, rough or sharp objects…

The disadvantages of a trailer

  • the installation of a coupling device on your vehicle is necessary (from £50 for the accessory itself, plus at least £200 for professional installation);
  • an increase in fuel consumption of around 32% on the motorway.
  • a modified driving experience.

What are the regulations for coupling a trailer?

  • UK rules on what you are permitted to tow vary depending on when you passed your car driving test. If you passed your car driving test after 1 January 1997, you’re now allowed to tow trailers with a Maximum Authorised Mass (MAM) of up to 3,500kg.
  • tow bars need to be type approved and meet EU regulations.
  • you must have an adequate view in your mirror of the road behind you.
  • you must display the same number plate on your towing trailer as on your car.

What are the guidelines for driving with a trailer?

Towing a trailer changes your vehicle’s response time and balance, so reduce your speed since the braking distance is longer. Make sure your load is balanced and secure well.

In conclusion, a roof box is a practical and economical solution if you need extra storage for your holidays but are not carrying a heavy load. On the other hand, a trailer is ideal if you need to transport heavy loads regularly, especially over long journeys.