Choosing the right roof box can be a bit perplexing and there are a lot of questions on a buyer's mind like "what size do I need?" or "what is the most aerodynamic shape?" In this article we will try to answer these perplexing questions. If you already know what you are looking for in a roof box check out The Best Cargo Box Review to find out what our testers thought of our top 5 choices.
As we grow older, sometimes our lives change and we are in need of more carrying capacity in our vehicles. Some people may be living in their vehicles, going between seasonal work or adventures, some may be considering buying a minivan for new additions to the family, or some people's weekend pursuits require hauling more gear than can fit in an SUV. If you cant afford to upsize, or if you're not ready to relinquish your more youthful vehicle in exchange for more space, you may decide to go with a roof top cargo box instead.
Hard or Soft?
Depending on what type of gear you are hauling, how much you want to spend, and how much storage space you have in your home, you'll need to decide if you want a soft sided roof "bag" style carrier or a hard-sided roof box.
Cargo bags definitely have their advantages: they are much less expensive than a roof box, they collapse down for easy storage when you are not using them, and you do not necessarily need a roof rack to install them. On the flip side, you are basically driving around with a soft-sided cooler strapped to your roof. They are not as durable or weather resistant as a cargo box, and they are less aerodynamically shaped (because they are usually square), which could affect your gas mileage.
If you want to transport large and/or heavy gear like skis, a hard-sided roof box is the way to go. Yes, they are more expensive and are big, bulky things to store when you are not using them, but they are much more durable, have a larger carrying capacity — and they look way cooler. If necessary, a cargo box can live on your car for multiple days — or months - in all kinds of inclement weather. They can take a beating much better, and no doubt they are easier to load and unload with lids that will stay open hands-free.
What to Look For in a Perfect Cargo Box
Now that you've decided to go with a hard-sided roof box there are a few things you'll need to consider before buying. They are: Size, shape, features, vehicle, and compatible roof racks. We'll go through this list item by item to help you make your choice.
Roof boxes come in all different volumes, from 10 to 20+ cubic feet. What will you be carrying in your roof box? You need to decide the maximum size you will need in length and height. Different models all have different load capacities, so you will need to decide how heavy the cargo you cart around will be, and if your roof racks can support that weight. If you are a skier or snowboarder, you will need one that is long enough to carry your skis and should go with a longer model like the Yakima Skybox Pro 16.
If you know you won't be carrying longer items, you can go with a shorter version like the Thule Sonic Large. There are also models on the market that are lower profile like the Inno Racks Shadow 16, but if you have taller items to put up there, you may want to go with something that's a bit higher like the Yakima Rocketbox Pro 14.
We all want to know how to save money on gas. Logically, we want a roof box that is as aerodynamic as possible to save us money (as well as to reduce road noise). We asked Yakima and Thule (we also contacted Inno Racks and Rhino Rack but had no reply), and asked them what they did to make their boxes aerodynamic.
We asked the Yakima design team about their design process and what they do to test the aerodynamics of their boxes. They said that their first concern when designing a product is the user experience. They design their boxes in practical shapes for the human element — which sometimes are not the most aerodynamic shape.
They do, however, have engineers who test for aerodynamics using a wind tunnel and computer programs where they are mostly looking for air/road noise and particularly turbulent areas that could create extra drag. Yakima also said that the gas mileage and aerodynamics depend on the vehicle and the user — how the box interacts with the vehicle — including the shape of the vehicle in relation to the box, where it is positioned on the vehicle, and how and where the person is driving. They are hesitant to assign any kind of coefficient of drag number (the system used to rate cars on their aerodynamics) to their cargo boxes because of these variables. Yakima has had people tell them that their boxes do not affect their gas mileage at all, just a little, and in one case even make their gas mileage better! In our tests, we noticed that driving around with a roof box on our car consistently reduced our gas mileage anywhere from 1 to 5 MPG, and it just seemed to depend on what kind of driving we were doing (highway vs. mountain roads) and how much cargo we had in our vehicles and in the box.
We did find that smaller, lower profile models like the Inno Racks Shadow 16 and the Thule Sonic had less road noise and handled better, so you may want to consider getting the smallest, lowest profile box that will still meet all your needs.
Yakima and Thule both agree that the interaction between your box and car are key to how the air moves over, under, and around your cargo box, which affects the aerodynamics of the whole thing. How and where you are driving is also just as important in terms of gas mileage. Therefore, looking for the box with the most aerodynamic shape should not be your number one deciding factor, since it seems like a bit of a crap-shoot. Instead, look for one that is practical, looks cool, and is easy to use.
Our favorite feature, that luckily all of the boxes we tested have, is the ability to open on both sides. This reduces a lot of hassle.
We also like the models that are easy to open with one hand for those times when you're wrangling gear, kids, or dogs. These easy-to-open boxes have the stiffest lids, such as the Thule Sonic, so they do not flop when you are opening. We love the latch handle on the Yakima Skybox Pro, making it so you can just pop it open.
We obviously want a box that is easy to install, especially if we are taking it on and off a lot, like we did in our tests. We think that the Rhino Rack Master Fit 550 is the easiest to install with its simple clamping system that came pre-assembled. You just turn a few knobs and are done. We are not so fond of Inno Racks Shadow 16's mounting system, which has a lot of assembly required, and the hooks look cheap and not very durable.
You may want to consider what type of vehicle on which you plan to install your cargo box. We found that our lead tester's Toyota Matrix seems too small for the largest model in this review, the Rhino Rack Master Fit 550, that has 19.5 cubic feet of space. We prefer boxes that are 16 cubic feet and smaller. If you have a larger vehicle like an SUV, truck, or minivan you could go with something larger.
Also consider how tall your vehicle is. There are low-profile boxes made specifically for tall vehicles, such as the Inno Racks Shadow 16, that can still carry a lot of cargo, but will not make your car 10 feet tall. Also consider if you are going in and out of parking garages frequently — you may need to figure out the maximum height your vehicle can be without causing a major incident! Lastly if your vehicle has a hatchback you'll need to make sure that the model you are considering will work with your hatchback, and that the hatch will not bang into it when it's mounted on your roof. Most manufacturers' websites will have this information. All of the boxes we tested in this review worked with the Toyota Matrix's hatchback, although the Master Fit 550 was close.
If you are in the market for crossbars or a roof rack system, most of the manufacturers' websites will walk you through your selection process, starting with what vehicle you have and if you have factory racks or a "naked roof". We like Yakima's website because it takes you through step by step to find the right rack. We have noticed that the shape of your crossbars will affect the wind noise in your vehicle. Square bars are the least aerodynamic shape, then round, then oval.
Fortunately, no matter what shape your crossbars are, all of the boxes we tested in this review have universal mounting systems — but if you are not buying one we tested, you should double check that the box you are buying will attach to your crossbars.