The SkyBox NX XL is the value pick at the top of the size chart: 18 cubic feet of genuinely usable space thanks to a flat floor, a taller nose for small bags, and a stiff three-rib lid, all for less than Thule's comparable box. It is heavy and a touch noisier with a sunroof open, but it is the best all-rounder for the money.
Full review
Real-World Performance
The SkyBox NX XL's reputation rests on usable space rather than headline volume. OutdoorGearLab, which scored it 76 out of 100, highlighted its "snag-free interior floor for maximum capacity storage," the flat floor letting bags, bins, and skis slide in without catching on ribs. GearJunkie added that "the larger nose allows duffel bags and small totes to be stowed up front, where normally you'd be wasting space," so the same cubic footage holds more real gear.
Loading is straightforward thanks to DualSide opening and a full-metal handle, and the quick-attach mount gives an audible click when it is locked down. The main in-use gripe reviewers raised was slightly more wind noise when driving with a sunroof open.
What keeps it near the top of nearly every list is the balance it strikes: it is not the flashiest box, but it pairs genuine 18-cubic-foot capacity and a durable, made-in-USA shell with a price well below the comparable Thule boxes. For buyers who care about how much real gear they can carry per dollar rather than the polish of the mount, that balance is hard to beat.
Build Quality and Design
Yakima molds three ribs into the lid, which makes the shell noticeably stiffer than single-piece boxes and helps it resist flex at speed. The box is made in the USA and ships with SKS locks. The nano-texture finish hides scratches and road grime. At 53 pounds it is the heaviest box in this group, a consequence of that rigid construction.
Better Trail, which scored it 4.7 out of 5, the highest of any box here, called it "the roof box we most often recommend to friends and family" and "easily one of the best all-around cargo boxes" thanks to its "durable build and reasonable price in an expensive category." That combination of stiffness, made-in-USA construction, and a price below the comparable Thule boxes is the heart of its value argument.
Capacity and Fit
With 18 cubic feet (about 510 liters) and external dimensions of 84 by 36 by 16.5 inches, the SkyBox NX XL matches the largest Thule boxes for volume and beats them on practical packing. It mounts to Yakima StreamLine, factory, and most aftermarket crossbars with a 24-to-40-inch spread. As with any 84-inch box, confirm it clears your windshield and hatch on a shorter vehicle.
The flat floor is the differentiator: where ribbed or contoured floors waste space and snag straps, the SkyBox's flush interior lets you slide in long, awkward items like skis and rolled gear without fighting the box. Combined with the taller nose that takes small bags up front, the effective usable volume is higher than the raw cubic-foot figure suggests, which is why reviewers single it out for packing efficiency.
Where It Falls Short
The extra wind noise with a sunroof open is the most-cited complaint, though it is minor. The 53-pound weight makes solo loading onto a tall roof difficult. And while the mount is secure and easy, it lacks the torque indicator that makes Thule's PowerClick foolproof. The long body also limits which small cars it suits.
How It Compares to Alternatives
The SkyBox NX XL is the value answer to the Thule Motion 3 XL: same 18 cubic feet, more usable interior, lower price, slightly less refined mount. It also undercuts the Thule Force 3 XL while offering a roomier floor. The budget RocketBox Pro 14 is a smaller, cheaper step down, and the INNO Wedge 660 is the low-profile alternative for tighter roofs.
Who It's Best For
Pick the SkyBox NX XL if you want the most usable large box for the money and value a stiff, durable shell. It is the smart all-rounder for road-trip and ski families who do not need Thule's torque-confirming mount. If you want that mount and the most premium finish, the Motion 3 XL is the upgrade; if you need less space, the RocketBox Pro 14 or low-profile INNO Wedge 660 fit smaller setups.
Value at This Price
The SkyBox NX XL is the value leader among the full-size boxes, and Better Trail's 4.7-out-of-5 score, the highest in this roundup, reflects exactly that: a "durable build and reasonable price in an expensive category." At around $849 it delivers the same 18 cubic feet as the Motion 3 XL for several hundred dollars less, with a flat floor that arguably packs more efficiently. You give up the Motion's torque-confirming mount and gloss finish, but not a single cubic foot of capacity. For most road-trip and ski families weighing space and durability against price, that makes the SkyBox the rational default rather than a compromise.
Strengths
- +18 cu ft of usable space, undercutting the comparable Thule boxes on price
- +Flat, flush interior floor lets large items slide in without snagging straps or ski edges
- +Taller nose stores duffels and totes up front where space is usually wasted
- +Quick-attach mount gives an audible click when securely fastened
- +Three lid ribs make the shell notably stiff and durable, made in the USA
Watch-outs
- −Reviewers noted more wind noise with a sunroof open than some rivals
- −At 53 lb it is the heaviest box here to lift onto the roof
- −Mount is good but lacks the torque indicator of Thule's PowerClick
- −Long 84-inch body can crowd shorter roofs
How it compares
Matches the Thule Motion 3 XL and Thule Force 3 XL at 18 cu ft while costing less than the Motion, making it the best-value large box. Its flat floor is roomier in practice than the boxes it competes with, and it dwarfs the budget Yakima RocketBox Pro 14 and the low-profile INNO Wedge 660.
Who this is for
At a glance: Buyers who want maximum usable volume and a stiff, durable shell without paying Thule's premium.
Why you’d buy the Yakima SkyBox NX XL
- 18 cu ft of usable space, undercutting the comparable Thule boxes on price.
- Flat, flush interior floor lets large items slide in without snagging straps or ski edges.
- Taller nose stores duffels and totes up front where space is usually wasted.
Why you’d skip it
- Reviewers noted more wind noise with a sunroof open than some rivals.
- At 53 lb it is the heaviest box here to lift onto the roof.
- Mount is good but lacks the torque indicator of Thule's PowerClick.
Rating sources
“Snag-free interior floor for maximum capacity storage”
“The larger nose allows duffel bags and small totes to be stowed up front, where normally you'd be wasting space.”
“The Yakima SkyBox NX XL ($849) is the roof box we most often recommend to friends and family.”
Our 4.6 score is the average of these published ratings. Ratings marked * were derived from the reviewer’s written analysis or video transcript — the publisher didn’t print an explicit numeric score, so we inferred one from their own words. Click through to verify. More about methodology.
