Car Roof Box FAQ

There are plenty of pros and cons to do with roof cargo boxes. If you regularly need to carry lots of luggage then you may wonder how you managed without one!

The primary factor to determine whether you want to buy or rent a box is really how often you think you’re going to need it. If you are only likely to use it for an annual vacation then you might be better off renting one just to see how useful it could be before committing to a purchase.

If you make a lot of trips every year where you need to carry extra luggage or equipment then you will definitely find buying a roof cargo box is the best option financially. 

Take a more in-depth look at whether to buy or rent a roof box.

A roof bag will be easier to store when you’re not using it but doesn’t offer the same protection for your belongings as a roof box would. 

Here is a handy comparison: Roof Bag vs Roof Box

Unless you have a vehicle that already comes with a way of attaching a cargo box then yes you will need to fit some form of roof bars first. You will probably find that the manufacturer’s own roof bars are the best option for your car. Failing that go for the roof bars that the roof box company recommends assuming they will work with your vehicle.

If you’ve never fitted one before then it may take you a little bit of getting used to. However,  the majority of boxes use some form of quick fit system so once you get the hang of it you will be able to install and remove your box pretty quickly.

Different insurance companies are likely to have different opinions so it will be best to check with your insurer directly. 

Some will be more secure than others. It depends to a degree on how much you are willing to spend. More expensive boxes will be made of higher quality materials and usually have better locking mechanisms.

Find out more about roof box security here.

Most roof boxes would probably be classified as water-resistant rather than strictly waterproof. Many manufacturers won’t go as far as claiming that their cargo box is totally waterproof but they will still do a good job of keeping your gear dry.

Most manufacturers recommended top speeds are around or just below the typical speeds you can take on highways or motorways in most countries so around 60 to 80 mph.

You would be advised to keep your speed down in order to maintain a reasonable fuel economy figure.

There’s no doubt that adding a roof box to your vehicle will reduce your fuel economy but it will vary depending on the size and shape and also how you tend to drive.

To find out how big an effect it may have and how to minimize the impact you should take a look at this article on how a roof box affects fuel consumption.

It’s usually best to remove the box when you don’t need it to carry cargo. For a detailed discussion, you should read this post.

You should avoid fitting Have a roof box that will overhang your windshield So much that it affects your visibility when driving. You should also avoid boxes that will stop you from opening the rear hatch.

There is more detailed advice in this article on overhang.

In theory, you could put anything in your roof box as long as you are within the weight limits specified by the manufacturer of your car. In practical terms however you should always try to use the roof box for light but bulky items. 

For more specific ideas check out my guide on what to put in your roof box.

It’s actually more of a question of the weight you will be able to carry on your roof. Many cars will have a limit of 165lbs or 75kg so this is as much as you will be allowed to carry and that includes the weight of the box and any roof bars. It’s always best to check with your vehicle manufacturer so that you are certain of your weight limits.

Generally speaking, it is possible to fit a cargo box even if you have a panoramic roof. However, you should really check with the manufacturer of your vehicle to be certain. There is also likely to be a lower weight limit than you would find on a similar vehicle without a panoramic roof. Click here for more information.

24 ft³ is the biggest box – Farad Marlin 680L. You can also get boxes from major manufacturers like Thule with a capacity of 22 ft³. Here is a rundown of some of the biggest boxes available.

You will probably do well to stick to using simple dish soap and water to clean your roof box. You can get more details in this guide.

This Is not a very good idea. You could damage the cargo box, your vehicle or worst of all you could damage the car wash mechanism. 
You can find more on this topic by reading this.

Different rental companies have different rules. Some may allow you to fit a roof box while others will supply a vehicle with one already fitted if you request it as an option.

You are unlikely to be charged any extra in this situation. Don’t forget though that most ferries will have a height restriction so you may need to clarify whether you can use your cargo box on any ferries that you think you’ll need to use during your trip.

The majority of roof boxes should be able to protect your belongings from the odd shower even if they don’t expressly describe themselves as waterproof.

However if you are likely to do a lot of driving in wet weather it would be best to check if the particular model claims to waterproof before making your purchase. It’s no good getting some extra storage space for your sleeping bags only to find they are soaked through when you arrive at the camp site!

Yes you will need some sort of roof rack in order to attach a roof box. Either crossbars from your vehicle manufacturer or a generic roof rack will do the trick. Rooftop cargo box manufacturers like Thule also make bars that can attach to the roof of your vehicle.

No, some boxes are too big for certain vehicles as they might overhang the front or obstruct your access to the rear of the vehicle. The mounting system used on the box might not be compatible with the roof rack you have installed.

While having all that extra space might seem tempting don’t fall into the trap of taking half your house with you on your next trip! While having a large box might seem like a good idea you are still limited by the load capacity for the box and the roof.