How do hitch mounted cargo boxes stack up against rooftop cargo boxes?

If you need extra cargo space, you’re probably familiar with the classic rooftop cargo box. However, hitch mounted cargo boxes are becoming more prevalent, but do their benefits surpass those of the roof box? Let’s compare attributes to see which one may work best for you. 

Size and capacity
Roof boxes come in many shapes and sizes. They are typically measured in cubic feet or liters. The smallest roof boxes may be only 10 cubic feet, which fit most vehicles, while the largest can be over 20 cubic feet, and really only fit best on large vehicles. They can be shaped in ways that maximize luggage capacity, or long and narrow boxes can work well to carry skis and similarly shaped items while leaving space for something like a bike rack next to it. Long rooftop boxes may prevent your vehicle’s rear hatch from opening all the way, so Thule and Yakima publish hatch clearance measurements so you can choose a box that will fit well on your car. They can typically handle between 100-165 pounds, but this will also be dependent on the carrying capacity of your roof rack, which may be less. 
Hitch cargo boxes range from about 9 to 14 cubic feet in cargo capacity and are usually rated for around 100 pounds of gear. Their width constraints make them less suited to carrying skis, but they are often boxier so they work well for luggage and duffel bags. 

Parking
Once you’ve determined the size requirements you need, parking options could dictate your choice for you. Street parking with hitch accessories, especially something that sticks out as far as a cargo box, can be difficult and frustrating. Your backup camera will be severely limited (and proximity sensors may need to be disabled), and the parallel parking spaces available to you may drop substantially. I consider the hitch cargo box something that is best stored in the garage and only installed when needed.
If you regularly park in a garage (either at home or a parking garage), the added height of a rooftop box may be just as problematic. Either way, make sure you know how high your car becomes with the rooftop box or how long it becomes with the hitch box in order to make sure the car fits where it needs to fit.

Fuel economy and noise
There are a lot of variables at play here, but a hitch mounted box will almost always be quieter and have a lesser impact on fuel economy and wind noise. This can be especially important for EV’s that rely on superior aerodynamics to achieve an acceptable range. For rooftop boxes, you’ll probably see at least a couple mpg drop, and may even be constantly reminded it’s up there from the wind noise on the highway. While in motion, the hitch cargo box has little impact on the driving experience and it is easy to forget it’s even there.

Access to cargo
It’s much easier to reach cargo mounted to a hitch receiver than on the roof, no doubt. However, a hitch cargo box may also inhibit your trunk or hatch from opening, which could be a problem. Some hitch cargo supports tilt or swing out of the way, but it’s nice when the hatch can open without having to do that. The rear hatch on my CX-30 has no problem clearing the lid of the Yakima EXO GearLocker when it’s closed. 
If you go with a rooftop cargo box, you’ll need to be able to reach above the roof or have something to climb on so contents are accessible. This also makes the rooftop box more unwieldy to install and remove, so it may just stay on the car all the time. 

Cost
Finally, cost. There are a lot of options for rooftop cargo boxes, so price varies quite widely. If your car doesn’t already have crossbars, you’ll need those too, so you’re looking at no less than $1,000 to get set up. Hitch cargo boxes often start a little higher, and you’ll need to factor in the cost of the trailer hitch if your vehicle is not already equipped with one. 

Options
Pictured at the top of the page is the Yakima EXO SwingBase (New or Return) and GearLocker. Yakima EXO is a modular hitch-mounted cargo and accessory carrier system for 2” hitch receivers. The EXO SwingBase unit can accept a range of different accessories, including a bike rack, ski rack, and even a cargo basket. EXO TopShelf is an add-on that allows you to combine accessory carriers, so you can have a cargo box on the bottom and a bike rack on top. 

Thule has two different hitch mounted cargo boxes. 
Thule Santu is a unique design that attaches directly to Thule Epos 2 or Epos 3 and EasyFold XT bike racks. 
Thule Arcos is a hitch cargo box designed to fit any of three different bases:
Thule Arcos tilt platform 2"
Thule Arcos tilt platform 1.25"
Thule Arcos Platform (non-tilting, but fits 1.25” and 2” hitch receivers)

Please note that with all of these hitch mounted cargo boxes from Thule and Yakima, the box itself is sold separately from the base unit that attaches to the hitch receiver. We can usually ship the base units within the Contiguous US, but cargo boxes themselves are only available at our Portland Retail Store.

Have other questions about carrying cargo on your car? Send us a message!