To find your roof box, whether you choose a new or a second-hand model, you must take into account several criteria:

car with a vintage roof box

The right volume

300 litres, 600 litres… It is not always easy to imagine what such large volumes correspond to.

In general, we can consider:

  • A large travel bag = 100 litres
  • One large suitcase = 200 litres
  • A Peugeot 206 trunk (without folding the bench seat) = 245 litres
  • A refrigerator (and its freezer part) = between 250 and 300 litres

But beware, roof boxes are (fortunately) not cubes. It will therefore be much easier to place flexible bags than large rigid suitcases.

The right length

The lengths of the roof boxes range from 105 to 218 cm. To find the one that suits you, take into account the size of your car, but especially what you want to transport:

  • long objects (skis, surfing…): you need a long roof box
  • bulky objects (stroller, crib): a compact or medium capacity chest may be sufficient

The compact and short trunks (volume from 315 to 370 litres) are suitable for urban and small family cars.

As for the medium and large capacity chests (the longest), which are the most sold. Thanks to their larger widths, they have capacities ranging from 390 to 570 litres, and are suitable for all types of cars, station wagons, minivans, 4×4s, SUVs and sedans.

Long roof box and small car, is that possible?

In theory, if the spacing of the roof bars allows it, it is always possible to put a long roof box on a small vehicle. On the other hand, you will have loud wind tunnel noises if the trunk protrudes to the front of the pavilion. Very unpleasant on long journeys! In addition, the more the trunk protrudes from the front of the roof, the more windward the grip is with a significantly higher fuel consumption. It is therefore strongly discouraged!

The right opening / closing system

Opening systems

  • Bilateral opening: The trunk opens on both sides, which is particularly convenient in the
    city to always load or unload on the sidewalk side, and also optimizes the loading of your trunk by filling in the gaps on both sides of the trunk.
  • Power-assisted opening: Less effort to open the trunk on the roof, which always stays open while you load it.

Locking systems

  • Centralized lock: By closing a single lock, two locks are activated simultaneously at different locations in the trunk for increased security (Multi-point lock principle).
  • Secure lock: Cannot remove keys if the trunk is open. It is therefore impossible to leave the trunk unlocked, or to forget your keys in the trunk.

What are the quietest safes?

The boxes are resistant to air, causing more or less significant disturbances. Less high, more aerodynamic and equipped with diffusers (such as racing cars), the profiled trunks are the quietest.

Choosing the right roof box to reduce fuel consumption

Air resistance affects your consumption (+15% depending on your speed).

An effect that you can always limit, on the one hand by favouring a model that is as close as possible to your needs in terms of bedding, and on the other hand by reducing your speed.