A vehicle roof storage solution, like a roof cargo box or rooftop cargo bag, can be the perfect way to increase your vehicle’s storage capacity. Our comprehensive buying guide helps you choose and install the right rooftop carrier for car based on your specific needs.
How to choose a roof cargo box
A hard-shell cargo box costs more than a rooftop bag, but it offers better protection. It keeps your gear dry and safe from weather conditions.
Check if your vehicle is compatible. Ensure that your car has the required crossbars or roof rack compatibility to mount the cargo box.
Checking the support and measuring the vehicle
A roof rack system lets you transport a hard-shell aerodynamic cargo box, bikes, skis, snowboards, canoes, and kayaks. It distributes weight evenly and prevents damage to your vehicle’s roof. Some racks are fixed, while others are adjustable, offering more flexibility.
How to choose a roof rack
Vehicle compatibility is key. Verify the following:
Make, model, and dimensions of your vehicle
Year and edition
Roof type (with or without gutters or factory crossbars)
Unsure? Visit manufacturer websites like Thule, SportRack, or Yakima to find compatible roof racks.
Have your Vehicle Identification Number (VIN) ready — it’s found in the lower corner of your windshield or on your ownership papers. Once you’ve selected the right rack, order it through our Online Boutique and earn CAA Dollars if you’re a member.
Here’s how to take accurate measurements:
Fully open your vehicle’s rear hatch.
Measure the distance between the front edge of the roof rack and the point where the roof meets the hatch. Stay centred for accuracy.
Measure the spacing between the crossbars. If your crossbars are adjustable, move them forward for more mounting options.
Then, compare these measurements with those given in the specifications of the boxes you’re considering.
Key features of a quality roof box
To choose the best rooftop carrier, consider the following:
Model: Some cargo box fits are designed for specific purposes (like skis, strollers, etc.), while others are more universal.
Material: ABS plastic is more durable than polyethylene, which may be affected by temperature changes.
Weight: Boxes range from 34 to 75 kg. Check your vehicle’s maximum roof load capacity (including cargo) in your owner’s manual.
Opening: Some boxes offer dual side opening. Otherwise, most open from the passenger side of the vehicle for a safe and easy access on the roadside.
Locking system: A good cargo box has a triple locking system and is secured from inside the vehicle.
Mounting system: Premium brands like Thule or Yakima offer easy-to-use quick-mount systems. Other models may require more manual adjustments.
Warranty: Some manufacturers offer a limited lifetime warranty.
Prices vary depending on material, size, and mounting system.
Cargo box installation and use: What you should know
Before installing a roof box, make sure your vehicle has a compatible support. Position your roof box centrally between the crossbars for better stability and aerodynamics. Poor weight distribution can damage the box. If it doesn’t close properly, reorganize your gear.
Install your box on your roof, in the middle of the bars, for better roadholding. It must not interfere with the driver’s vision.
Correct the position of the box if necessary: when you’re facing the vehicle, it should be well centred and parallel. The tailgate must open and close properly.
Secure the fastening system so that you can close the box easily.
Most rooftop cargo boxes are designed for a cruising speed of up to 120 km/h. Always follow the speed recommendations provided by the manufacturer.
Expert’s insight
«L’ajout d’un coffre de toit peut augmenter votre consommation de carburant de 5 à 15%, en raison de la résistance au vent. Les coffres avec une forme aérodynamique (comme les coffres de toit Thule) permettent de diminuer cet impact. Pensez à retirer votre coffre si vous ne l’utilisez pas pendant de longues périodes et remisez-le à plat pour éviter de déformer sa coquille.»
How to choose a rooftop cargo bag: A budget-friendly alternative
When it comes to rooftop storage for small cars, a roof cargo bag is a more affordable solution. It’s lighter, easier to install, and doesn’t require a permanent roof rack — but offers less security against theft. An anti-theft locking system is highly recommended. While waterproof, performance may decline in heavy rain.
Tip: Remove your rooftop bag when not in use to extend its lifespan.
Installing a rooftop bag
Some rooftop bags are secured with straps, while others use hooks and straps that attach under the door frame.
Good to know: A loose strap can scratch your vehicle’s paint if it detaches during driving.
Safety and legal regulations
Before setting off on a road trip, ensure your cargo box or bag complies with local transportation laws. According to the Highway Safety Code:
Your load must not exceed the vehicle’s dimensions by more than:
1 metre at the front
2 metres at the rear
Cargo must never:
Be poorly secured or at risk of falling
Obstruct the driver’s field of vision
Cover lights, headlights, or the licence plate
Compromise vehicle stability or safe driving
Be mounted or tied in a way that violates load securing regulations
Whether you choose a rooftop bag or a roof box, always double-check the dimensions and weight capacity. Make sure the product is compatible with your vehicle. And before your trip, review your insurance policy to ensure you’re properly covered.
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