Roof Box vs. Hitch Rack: How to Carry Bikes, Skis and Cargo

When the trunk is full, gear has to go somewhere else: up on the roof, out on the hitch, or into a truck bed. Each spot has trade-offs in fuel use, trunk access, clearance and how much weight it can safely hold. This guide walks through the main options for bikes, skis and cargo so you can match one to your vehicle and the way you travel.

The main options at a glance

Roof boxes and roof mounts

Roof carriers sit on crossbars, so you first need a roof rack that fits your vehicle. Rack makers publish fit guides by make and model. Once the bars are on, you can add a cargo box, bike mounts, ski and snowboard carriers, or a basket or platform. The big advantage is that everything stays out of the way: your liftgate or trunk opens normally, and nothing hangs off the back of the car. You can find bars, feet and roof systems in our roof racks section.

Weight: three limits, and the lowest one wins

Every roof setup has three limits: your vehicle’s roof load limit (in the owner’s manual), the rack’s rating, and the box or carrier’s rating. Use the lowest. Then subtract the weight of the rack and the empty box. What’s left is how much gear you can actually load. Use the vehicle’s dynamic roof limit, which is the one for driving, rather than a static figure.

Roof boxes work best for gear that’s bulky but fairly light, such as skis, sleeping bags and clothing. Heavier items are better kept inside the vehicle. Inside the box, put about half the weight in the middle, between the crossbars, and split the rest between the front and back.

Fuel economy and noise

Anything on the roof sits right in the airflow. The U.S. Department of Energy’s fueleconomy.gov says a large, blunt rooftop cargo box can lower fuel economy by roughly 6% to 17% on the highway, and by 10% to 25% at Interstate speeds of 65 to 75 mph. Rear-mounted cargo boxes or trays cost far less, about 1% to 5% on the highway. The same site notes that removing an external cargo container when you’re not using it saves fuel. Roof gear can also add wind noise at speed.

Clearance: the garage problem

A roof box or a bike on the roof adds real height, and it’s easy to forget it’s there. Garages, parking decks, drive-throughs, car washes and low branches are all risks. Measure your total height with the gear loaded, and leave yourself a reminder, such as a note on the dashboard or on your garage door opener. If your home garage is tight or you already drive a tall SUV, that alone may push you toward a hitch option.

Skiers get a bonus from a long roof box: skis and boards ride inside, protected from road salt and grime. Compare your longest skis to the box’s inside length before you buy. Browse boxes and baskets in cargo boxes, baskets and bags.

Hitch bike racks: receiver size and style

Hitch racks slide into a receiver on the back of your vehicle. Loading is easier than on the roof because you never lift a bike over your head, and the bikes ride behind the car rather than on top of it.

1.25-inch vs. 2-inch receivers

Receivers come in two common sizes. Class 1 and Class 2 hitches have a 1.25-inch opening and are found on many cars, crossovers and minivans. Class 3 hitches have a 2-inch opening, the size you’ll see on most pickups and SUVs. A rack is built for one size or the other, so measure the opening before you shop. Your vehicle and your hitch each have a tongue-weight rating, and the rack plus the bikes count toward it. E-bikes and other heavy bikes need a rack rated for their weight.

Platform vs. hanging racks

• Platform (tray) racks hold bikes by the wheels, so nothing clamps the frame. That makes them a good match for carbon frames, fat tires, e-bikes and unusual frame shapes, and they’re the usual pick for heavier bikes. Many platform racks also tilt away from the vehicle.
• Hanging racks hold bikes by the frame on arms. They’re straightforward and can carry several bikes in a compact space. Step-through, kids’ and full-suspension frames may need a frame adapter bar to hang properly.

Check rear access, too. Tilting racks angle down so you can open the liftgate, and swing-away designs pivot to the side. Test whether yours can do that with bikes loaded. Brands such as Yakima, Thule, Kuat and Rocky Mounts make hitch racks, and some racks accept add-on trays for extra bikes. Compare racks and add-ons in our bike racks collection.

Hitch cargo carriers

A hitch cargo carrier is an open platform or an enclosed box that mounts in the receiver. It’s a good home for coolers, storage bins and gear you don’t want inside the car. It sits low and behind the vehicle, so it’s easier to load than the roof and costs less fuel than a roof box. You can compare platforms and boxes across our car racks collection.

• Do the tongue-weight math. Take the lowest of your vehicle’s rating, the hitch’s rating and the carrier’s rating. Subtract the weight of the carrier (and the box, if it has one). The rest is your cargo limit. Put heavier items low and close to the bumper.
• Keep lights and plate visible. A loaded carrier can hide your license plate, brake lights or turn signals. Check your state’s rules and make sure other drivers can see your signals.
• Mind the exhaust. Check the gap between the tailpipe and the carrier, since hot exhaust can damage the carrier and your gear.
• Remember the extra length when backing up, parking and pulling into a garage.

In winter, anything on the back of the car catches road spray and salt, so an enclosed box or a covered load keeps gear cleaner.

Truck-bed options

Pickup owners have a built-in cargo area, but a bed alone isn’t always enough. Bikes in the bed need to be secured so they don’t slide or tip. Bed racks raise a set of bars above the bed rails, which lets you carry long gear like kayaks or paddleboards up high and mount roof-style accessories, such as bike carriers or a cargo box, while leaving the bed free underneath. Some bed racks can work with certain tonneau covers through an adapter kit, so check compatibility if you already have a cover. Check both the rack’s load rating and your truck’s payload before loading up. See our truck racks, towers and shells.

Security and everyday use

• Lock what you can. Many roof boxes lock, and many racks let you lock bikes to the rack and the rack to the vehicle. Even so, don’t leave valuables in an exterior box overnight in a public lot.
• Check straps and bolts after the first few miles and at every stop.
• Take it off when you’re done. An empty box still sits in the airflow, and removing a cargo container you aren’t using saves fuel.
• Follow the maker’s instructions for installation, speed and load limits.

How to choose

• You haul skis, snowboards or luggage and need the rear hatch: a roof box.
• You carry bikes, want easy loading and have a hitch: a hitch bike rack, with a platform style for heavier bikes.
• You carry heavy or dirty gear: a hitch cargo carrier, within your tongue-weight limit.
• You drive a tall vehicle or park in a low garage: a hitch option avoids overhead clearance worries.
• You drive a pickup: the bed, or a bed rack for long gear.

You can see everything in one place in car racks and auto. Heading to the mountains with that new rack? Make sure your tires are ready for snow, too: read our comparison of winter tires vs. all-season tires before the first storm.