Everything You Need to Know About Rooftop Cargo Boxes: Beginner's Guide

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Quick question: What things have you wanted to bring to that vacation or road trip, but you've been lacking space? –If you are a person that longs to live an active lifestyle, then your answer may revolve around backpacks, boots, tents, skis, etc. And in all honesty, these things are the most necessary appendages to make that outdoor adventure more fun and comfortable.

What about the trunk? This is a very convenient place for most people because almost all cars have it. However, the bulky gears you might need to add or your plus one's items may not fit. And of course, you don't want to travel with a half-closed trunk, right? Owing to this type of risk and the proliferation of your items flying away, it's crucial to find a better solution. And in this case: a rooftop cargo box.

Unsurprisingly, the popularity of roof cargo boxes is rising at warp speed. This demand is an assured guarantee to the prospects that these cargo boxes are the best in adding the storage capacity for your car. And if this is what you have been looking for, this article contains breakdowns of everything you might need to know.

So, read on…

What is a roof cargo box?

roof cargo box is an additional storage space that helps keep the inside of the car organized and more comfortable. And not only this, but it also allows you to haul all your gears without leaving any behind. It is a type of cargo carrier that is sleek and works with the aesthetic of your car without sabotaging your gas mileage.

roof box cargo provides a more secure space for your gears. It comes with rack/bar attachments and lockable lids that keep your items shell-enclosed. Additionally, it sticks out into the wind due to its aerodynamic design.

This storage accessory doesn't limit you. So, whether you are driving a large SUV or a small hatchback, the roof cargo box will fit. Of course, there must be a roof rack with crossbars already installed. It may take a fiddling to get the cargo box on your car's roof, so be prepared. Once you get your roof box, the universal mounting hardware that comes with it helps you attach it with ease. A cargo box can be attached with a crossbar that is either:

  • Round
  • Square
  • Aerodynamic
  • Factory

While attaching it, ensure that the rear hatch can open up without hitting or interfering with the cargo box.

Why do you use roof boxes for?

Roof boxes are a great way of freeing up space. And for a great adventure, it can go a long way in ensuring there is safety— once you clear the load inside the car, you can check the rear-view mirror without being obstructed. So, roof boxes can be used for storing things like camping equipment, fishing gear, suitcases, Golf club equipment, and so much more.

Are roof boxes a good idea?

Purchasing a roof box requires you to know the pros and cons. Below are a few that will help you decide on the best product for you.


  • They are an excellent investment.
  • They provide extra space.
  • They are great for adventures.
  • They keep your items safe.
  • They are long-lasting


  • They negatively affect the gas mileage.
  • They limit the places you can visit and drive through.
  • They are pretty expensive.

How to choose a roof cargo box

In as much as the roof cargo box serves you in a significant way, there are several factors you have to consider before purchasing one. This is mainly because cargo boxes tend to be expensive ($400 -$800). And for such a price, you need to know what aspect to consider regarding value for your money. 

With several companies manufacturing quality cargo boxes, like Thule finding a perfect one can be a hassle. You have to go through all the nitty-gritty work. Luckily, we have discussed several of and most essential factors that you should consider:

Does your car have a roof rack?

Begin by checking if your car has a factory-installed rack with the type of cargo box you have in mind. In cases where it is absent, you can purchase one and install it. Then proceed with checking your vehicle's manufacturing website or owner's manual. This will help you determine the capacity of your vehicle's roof.

What do you want to store in the cargo?

This is the topmost question you should ask yourself before heading on to consider other factors. For example, are you running for a vacation/adventure? – things like strollers, holding tents, ski poles, camp furniture, sleeping pads, etc., are some of the things you might have in mind. Once that is answered, the 'finding the correct dimensions' part should be easy.

Here are more points to consider as you think of the items you want to carry:

Weight of your item

The type of items you want to store in the cargo box should solemnly depend on the weight limits of the box. The maximum weight capacity in most cargo boxes ranges from 150 – to 165 pounds. With this information, ensure that whatever you put in doesn't match the maximum weight offered. Give it an allowance of like 10 pounds. Then, if you have heavier things like bins full of coolers, you can stow them in the car.

length of your item

Snowboards and skis can fit in your cargo box perfectly— of course, if the ski length matches that of your box's internal length.

lightweight and bulky items

The light ones fit in perfectly because the roof box cannot accommodate heavy things. So, things like camp chairs and sleeping pads which can take up a lot of space in your car can be ideally stored in the roof boxes.

Dimensions of cargo boxes

You should have weighed your options and seen what would fit best in the cargo box and what would not from all the information provided above. So, the next step is finding the correct dimensions for the cargo box.

These storage accessories come in two different variations, i.e., long and short. And all this is determined by what you want to put in it. For instance, a more temporary box is best for a road trip since it can fit boots, etc., while a longer one would work best with snowboards and specific ski boards.

  • The length of most cargo boxes ranges from 6 feet long to more. This means that for a 180 cm skiboard, a normal 6-foot box would serve the purpose.
  • A cargo box height may limit the places you can go. So, pay attention to the cargo's height considering the areas you are most likely to go in, i.e., the garage. But regardless of this, it is always good to keep in mind that you have a cargo box on the roof while adventuring or touring—just for safety.
  •  Most people tend to choose a wider cargo box. This isn't a surprise since the wider it is, the more storage capacity it will provide. However, as good as this deal may sound, there is also a downside. A wider cargo box may take up all the space on the rack's crossbar, denying you a place to place your kayak rack or bike rack. So, you can choose a narrower box— just to be safe— or get crossbars that are a bit wide.

What size roof cargo box do I need?

The height, width, and length are the gear capacity of a roof box. Unfortunately, this is a factor that not so many people consider. This leads to them missing out on the critical part of the apples-to-apples comparison of how much each box can hold.

Roof cargo boxes come with a space that can be 10 cubic ft up to 20 cubic ft. So, whether you have a Suburban or a Honda Civic, the options are plenty. But then again, the size will still influence your choice in that for a Suburban, you will have to choose a bigger box since it already has existing storage.

So, what amount of gear can a cargo box hold?

  • 12 cubic ft. / 340 liters or less can fit gear for up to 2 people
  • 15 cubic ft. / 425 liters can fit gear for up to 3 people
  • 18 cubic ft. / 510 liters can fit gear for up to 4 people
  • 21 cubic ft. / 595 liters can fit up to 5 people

Bigger boxes have proven to be the most bought ones. Their popularity is due to their way of accommodating more items. But they aren't necessarily the best options—well, if your items can still fit in the smaller ones.

One of the biggest reasons supporting this is their cumbersomeness. This is because the bigger the cargo box, the heavier it is. Another reason is their cost—more money is needed for extra capacity.

What about noise? Are roof boxes noisy? Bigger boxes have a huge surface area. As you drive, more air and wind are hitting the roof box. This makes the bigger roof boxes produce more noise than the small ones.

Impact on fuel: The weight exerted on your roof impacts your car's fuel efficiency. And once you add a huge roof box then the effect becomes more. So if you really don't need a huge box, do not get one.


Getting a cargo box that has more and better features may cost you more but at the same time serve you better. Here are some of the features that can make a roof cargo box easier to use:

  • Some boxes can open on both sides, thus saving you the energy you'd have used to retrieve cargo.
  • Other boxes have a front hinge that can allow you to easily reach your cargo. However, they may be less convenient while latching and unlatching.
  • To prevent shifting, tie-down straps that are found inside the box come in handy.
  • If you are afraid that your cargo will get scratched or snagged, then consider a cargo box that's screws, rivets and bolts are internal.
  • roof box with a clamping feature goes a long way as far as installing and removing it.

Types of the Roof cargo box

Again, this factor still depends on the type of luggage you want to carry. Most cargo boxes can accommodate up to 110 pounds. This should always be a consideration since some of the cars can only hold a weight of 100 pounds or less—including the cargo box, the roof rack, and the cargo itself. But if you assume this, the vehicle's top becomes heavy, thus raising its center of gravity which will all know makes the vehicle prone to rolling over.

Can you fit a suitcase in a roof cargo box?

This depends on the type of cargo box you choose. There are three types of roof cargo boxes, namely:

  • Luggage boxes: This is the ideal cargo box to store in your suitcase—so, yes, you can fit a bag in. In most cases, it weighs about 30 pounds and is about 3 feet wide by 5 feet long. These dimensions, plus the weight, allow you to haul in your suitcase and other short and bulky items.
  • Wide Sports Boxes: These are the most priced and the heaviest (40 pounds) types of boxes. They are best for skis and kayak paddles since they are usually 7 feet long. Their width (2 ½ feet) allows them to still fit more gear. They, however, may prevent the trunk from opening in some vehicles.
  • Narrow Sports Boxes: Are you a sports enthusiast? Well, this should work for you. The tiny sport boxes are usually 1 ½ foot wide, thus leaving a space for your bike or kayak. It weighs about 30 pounds. And just like the Wide sports boxes, the 7 feet length restricts the hatch and the trunk from opening.

Lastly, will it fit?

Now that you have identified your almost-to-be roof box, it's time to click the buy button. But, before that, will the specific roof cargo box fit nicely on your car? If you are not sure, head on and check the following aspects?

Hatch clearance

Testing the hatch clearance is an essential aspect to consider. An SUV or a hatchback with a rear door is an excellent remedy for the cargo box to interfere with the hatch clearance. But, on the other hand, this will promote it by not allowing the door to open. So, what do you do? Check the measurement of your hatch clearance to that of the roof box and compare? Well, if it works, it's a good idea. But if it doesn't, then…

  • You can also use a tape measure to determine this. Just measure your vehicle's center front crossbar up to the open back hatch at the same level as your crossbars.
  • If you are ordering online, but the store isn't as far away, you must drive to the shop for a specialist to check that.

How to pack a rooftop cargo box

With all that information, you might be wondering what to consider next. There are several more things to read on the roof cargo box. But the most important one is how you should pack a rooftop cargo box. Of course, you do not want to throw things in, so here is how you should fill them:

As mentioned above, lighter items are best stored in the cargo box. So, once you've packed everything you want to be kept, ensuring it doesn't surpass the weight capacity of both the vehicle and box, place half of the load on the crossbars (overtop and in between). The first quarter should be in the front, whereas the remaining should be in the rear. Ensure that you keep all the vulnerable things away from the edged and the base.

This simple procedure will save you from the unthinkable. And lastly, since the roof cargo box can be damaged or even the cargo by several elements, you must wrap it up with a dry bag.

Do the looks of a roof cargo box matter?

They definitely do! –most especially if you are an aesthetic person. From the color to the finishing, envisioning it beforehand can go long. Here are three main things to consider as far as the looks of a cargo box are concerned:

  • Color: The color of your box definitely says a lot about your choice. For example, a silver cargo box portrays a car owner who is a tech lover with sophisticated taste. Whereas a white color may represent a calm and graceful person.
  • Size: Buying a roof cargo box that is bigger or smaller than your car's roofline should be avoided. Consider a longer box if you drive a bigger car like an SUV or a pickup truck. But if your car is a sedan, then a longer box wouldn't be the right way to go.
  • Finish: Whether a matte textured finish or a shiny, sleek finish, the main goal is to have more space, right? However, if you have the chance to add more glamour to your car, then go for it! The matte finish is best for dusty and woody places since it doesn't show as much dust or scratch—this doesn't mean that you shouldn't handle it with care. The shiny ones are best for adding stickers.

Why are roof cargo boxes expensive?

You might be wondering, is a roof cargo worth buying? Well, that depends. You cannot invest more than $600 on something you don't entirely need. So, let's check why they are expensive first.

Roof cargo boxes are not just metal bars with an overpriced tag. Instead, the price comes from the manufacturer's consideration of delivering a high-quality design with great features, capabilities, and engineering. All these specifications contribute to the price.

Below are the components that make a roof cargo expensive:

  • High-quality materials: The design of a roof box is essential. However, if the quality is as good, the storage accessory can likely be high cost. For a sturdy and durable design, high-quality materials should be used.
  • Aerodynamics: The cargo box is exposed to the wind all the journey long. So, it needs to have an aerodynamic design that can help it withstand wind. If not, the wind might push down on the rack and add more weight to it, leading to the cargo lifting the car. A well-designed roof box should evenly allow air to pass under the rack. What about the gas mileage? A heavy roof box increases the drag. This is why you find that as you speed up, the gas-burning becomes more. So, to conclude this, the box should be able to reduce the drag to increase the gas mileage.
  • Weight Distribution: the parts touching the car (contact points) should be evenly distributed. This means that the stress should be evenly distributed for a heavily loaded box to avoid damage to the vehicle's roof. Do roof boxes damage your car? This mainly happens if the weight is exerted on one contact point. For example, if you drive at high speed, the wind will insert more pressure which may shift the weight of the cargo to the rear rack. If this happens, the force may damage the car's roof.

Is a roof box worth it?

If you have been struggling with a messy situation in your car, it's definitely worth it. A clean and more organized space brings both comfort and relaxation. And for a trip or vacation, you need all that. So, instead of shoving your stuff in the car, get a roof cargo box with the features you envision and consider your budget.

Problems associated with cargo boxes

Like any other thing out there, a cargo box is prone to problems. Here are a few that you might come across:

  • Overloading: an overloaded cargo box can cause damage to the hinges, thus denying your luggage 'privacy.'
  • Broken hinges: As time goes by, the hinges of cargo may weaken, so ensure you take great care of it, as instructed in the manual, and enjoy the longevity.
  • Broken keys: If you happen to get a company that makes a great and sturdy lock system, then this should be the least of your worries.
  • Knocking on things: Most roof cargo damages result from being hit. It is good to remind yourself that the space you want to go through should be more than two feet higher than your car.

How to fix a broken roof box?

Well, knocking on things can be extremely frustrating. But this shouldn't be of any worry. You can DIY! If it's just damage that isn't that bad, you can follow the following steps. It is also good to take it to a professional so that they can determine the severity.

  • Get the right products for the repairing process.
  • Go ahead to repair the damage, i.e., if there is a hole or crack present, adhere some thick yet strong plastic over, using epoxy. Cover the damaged area entirely and dry it. Once you are done, smoothen the surface by sanding it down.
  • If the roughness and unevenness don't get solved, tape the area and add layers of spray. Do this until it's thick, then spread it with a putty knife. Allow it to dry.
  • Remove the tape and then head on to retaping so that the affected area doesn't get the spray paint. Spray the site, ensuring it matches the color of the cap.

Once you are done, you can attach your 'new' cargo box to your car.

Handful roof cargo box tips

  • Do not forget that you have a roof cargo box on your roof.
  • Ensure your cargo is secure before commencing the journey.
  • Keep the height of the cargo box with the vehicle in mind.
  • Keep your box in a cool, dry place.
  • Always remember to lock your cargo box.
  • Remember that these storage boxes are not waterproof, nor are they dustproof.
  • Avoid putting items you often require in the box.
  • Ensure that weight is distributed between the crossbars.

Can I drive with an empty cargo box?

For your safety, avoid driving around with an empty box. This is because it is more likely to be pushed over by the wind, which may cause a noisy drive. Additionally, exposing your roof cargo box to an unforgiving climate may shorten its lifespan. So, if it's not in use, then remove it. Ensure you store it in a cool, dry place, with the base on the floor. You can also hang it flat against the wall.

How to Install roof cargo boxes

  • Install anchor points inside your roof box (could be U-brackets/bolts). Push the sliding block screws from the bottom of the roof box and thread the clamp plates from the top. Screw the bolts loosely. Repeat for each of the 4 anchor points.
  • Place the roof box on the roof rails (PS: It's advisable to find help).
  • Slide the roof box to the left of the carrier rails and the sliding blocks into the roof bar carrier. Repeat for the right side.
  • Align the roof box centrally and tighten all clamping bolts on the sliding blocks.
  • Done! Pack your luggage and drive off.

You can watch a video that shows the general assembly process of a rooftop cargo box here.


I've given you all the information you need to make an informed decision. Now it's your turn! Think about what roof cargo box is best for your needs and budget, then find one that meets those specifications on Amazon or at another retailer near you. You can always come back here if you have any questions before making a purchase. Good luck with your search!

About the author 

Vieira Babeker

Hi! I'm Vieira. I've always been interested in different Auto Accessories

My passion here at theroofboxes.com is to provide helpful straight forward clear advice and tips for Automotive Accessories.

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