Things to consider before getting a roof box

You might have many questions when searching for the perfect roof box. Can it be opened from both sides? Is the roof box equipped with quick fastenings? How much can it carry?

But what is the most crucial parts, and what can you do without? Niklas Byvik, the product manager for accessories at Volvo Car Sweden, says that one aspect is often overlooked when it comes to buying a roof box.

“Many assume that a roof box is safe, but unfortunately, it's not a given.” Niklas highlights two key safety points for roof boxes: ensuring it stays firmly on the roof during sudden stops or collisions and that it's built strong enough to keep your items secure inside.

“Unfortunately, there are several examples of roof boxes releasing from the roof and flying off like a projectile during heavy braking or a collision. The same goes for its contents. Skis can come out of the roof box while still attached to the car and potentially break the rear window of the car in front of you.”

Before buying, read independent tests of different roof boxes and find out at what speeds they have been crash-tested. According to industry standards, the roof box should withstand a collision at 30 km/h. Volvo Cars roof boxes are developed to withstand collisions up to 40 km/h, corresponding to 12 g-forces. But this assumes that you do not load the roof box with more than what it is designed for – in most cases, 75 kg.

“It’s good to keep in mind that roof racks also have a maximum weight for which they are designed. Be careful that the total weight – the roof box's net weight plus the load – does not exceed the capacity of the roof racks. A roof box can weigh anywhere from 6 kg to just over 30 kg. Since the weight of the box determines how much you can load on the roof, it's a purchasing factor,” says Niklas, emphasising that overloaded roof racks can damage the car's roof.

“A roof box also increases aerodynamic resistance, negatively affecting fuel consumption. Today, all roof boxes are more or less streamlined to reduce aerodynamic resistance. But expect an increase of about 10 percent of the car's fuel consumption.

“Therefore, finding a roof box that compromises a sufficiently streamlined design and good interior space is important, as it's impossible to have both. When they’re not needed, remove both the roof box and roof racks to reduce aerodynamic resistance and thus fuel consumption,” he says.

You might be thinking that the roof box is for storing your skis and that it is only for winter-season outings. But Niklas shares that the roof box is just as useful for summer escapades.

“Many leave the roof box in a garage during the summer and instead fill the car's luggage compartment to the maximum, which is not always very safe or practical. A roof box is an equally good and safe way to transport items during summer travels.”

Here’s a checklist to help you before buying a roof box

• Can the box be opened from both sides?
• Is the roof box equipped with quick fastenings for easier installation?
• What is the maximum load for my roof racks?
• How much does the roof box weigh?
• Are there loops or hooks in the box to secure the load?
• Is the bottom of the box padded so that sound does not enter the passenger cabin?
• Is the lock of the roof box easy to handle?
• How waterproof is the roof box?
• Does the design of the roof box suit my needs?
• At what speeds has the roof box been crash-tested?
• Is the roof box I plan to buy included in any independent tests?

So, ready to get your roof box? Find out more here: Volvo Winter Car Accessories | Volvo Cars