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Thule Motion XT Rooftop Cargo Box - 18 cu ft - Black Glossy

Thule Motion XT Rooftop Cargo Box - 18 cu ft - Black Glossy

Item # TH629806
Our Price: $949.95
You Save: $556.89
Roof Box
This item qualifies for Free Truck Freight Shipping
Shipping Weight: 46 lbs
In Stock
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84-1/2 x 36 x 17. Roof box mounts to your crossbars with PowerClick clamps. Locking lid opens from either side of your vehicle. Great for carrying skis, snowboards, and other gear on crossovers and mid-size wagons. Durable ABS plastic construction. Great Prices for the best roof box from Thule. Thule Motion XT Rooftop Cargo Box - 18 cu ft - Black Glossy part number TH629806 can be ordered online at or call 1-833-496-1390 for expert service.
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  • Reviews (475)
  • Q & A (0)
  • Photos
  • Why etrailer?

Thule Roof Box - TH629806

  • Aero Bars
  • Elliptical Bars
  • Factory Bars
  • Round Bars
  • Square Bars
  • Large Capacity
  • Thule
  • Long Length
  • Black
  • Dual Side Access
  • High Profile

84-1/2 x 36 x 17. Roof box mounts to your crossbars with PowerClick clamps. Locking lid opens from either side of your vehicle. Great for carrying skis, snowboards, and other gear on crossovers and mid-size wagons. Durable ABS plastic construction.


  • Cargo box mounts on your vehicle's roof rack to provide enclosed storage for your gear
    • Perfect for carrying sports equipment and large luggage for up to 4 people
    • Great for mid-size wagons and crossovers
  • Dual-side-opening lid lets you load and unload gear from either side of your vehicle
    • Push buttons, outer handles, and internal lifters make it easy to open and close lid
  • SlideLock system with One-Key System locks ensure your cargo is secure
    • Lid locks automatically once it's completely closed
    • Red Indicators let you know if lid isn't closed securely
  • PowerClick quick-release clamps provide easy, tool-free installation on most crossbars
    • Simply turn dials until they click to secure the mounting clamps to your roof rack
    • Mounting assemblies adjust along tracks to accommodate different crossbar spreads
  • Aerodynamic shape helps minimize wind noise and drag
  • Tapered tail end provides superior hatch clearance
  • 3 Load straps and 6 integrated anchor points let you secure cargo inside the box
  • Durable, ABS plastic construction resists impacts, scratches, and UV rays
  • High-gloss black finish
  • Made in the USA


  • Application: round, square, aero, elliptical, and most factory crossbars
  • Carrying capacity: 18 cu ft
  • Weight capacity: 165 lbs
  • Ski capacity: 5 - 7 pairs of skis
  • Snowboard capacity: 3 - 5 snowboards
  • Maximum ski/snowboard length: 200 cm
  • Exterior dimensions: 84-1/2" long x 36" wide x 17" tall
  • Interior dimensions: 79" long x 31-1/2" wide x 15" tall
  • Distance from top of crossbar to top of cargo box: 16"
  • Box weight: 46 lbs
  • Limited lifetime warranty

Note: Because of the size of this item, it ships via truck freight and only to the contiguous United States.

Thule SUP Taxi XT Crossbar Requirements

Thule Motion XT XL Cargo Box

Cargo boxes, bags, and baskets are great for transporting gear on your vehicle's roof. A cargo box has the added benefits of an aerodynamic shape that reduces drag and wind noise, a hard shell to protect your gear, and a higher degree of weather resistance. And you can latch and lock a cargo box for added protection against theft.

The Motion XT XL has 18 cu ft of storage space for golf bags, luggage, skis, snowboards, and other gear. The aerodynamic, low-profile design helps to reduce drag and wind noise, and the locking lid conveniently opens from either side of your vehicle. The box has internal tie-down points for securing cargo, and the PowerClick mounting system offers easy, tool-free installation.

Durable Construction

Thule Motion XT XL Cargo Box Aerodynamic Design

This cargo box is constructed of durable ABS plastic that is lightweight yet rigid and impact resistant. It has a glossy black, gel-coat finish that is stylish and less susceptible to chips, scratches, and harsh UV rays when compared with paint.

Dual-Side-Opening Lid

Thule Motion XT XL Cargo Box Dual Side Opening Lid

The Motion XT features a dual-side-opening lid so you can load and access your gear from either side of your vehicle. Integrated, grip-friendly handles help you easily open and close the lid even with one hand. The lid has lifters that ensure it opens and closes smoothly. There is also a convenient pull cord on the inside that helps you close the lid.

SlideLock System

Thule Motion XT XL Slide Lock System

The cargo box has SlideLock locks on each side of the lid. These locks have built-in indicators that let you know if the box is properly latched. The keys cannot be removed from the locks unless the lid is closed and locked. This prevents you from driving with an open or unlocked lid. The locks include Thule One-Key-System cores so you can swap them out to make all your Thule accessories keyed alike.

PowerClick Mounting System

Thule Motion XT XL Cargo Box PowerClick Mounting System

The box can be mounted on your vehicle in less than 5 minutes with the PowerClick mounting system. These clamps adjust along tracks in the floor of the box to accommodate different crossbar spreads.

Thule Motion XT XL Cargo Box Dials

To install the box, set it on your roof rack and center the clamps over your crossbars. Then simply turn the dials to tighten the clamps around the bars. The dials click when the clamps are secure.

Cargo Tie-Down Points

Thule Motion XT XL PowerClick Assembly

The PowerClick assemblies on the inside of the box have fixed anchor points for securing your cargo. Just loop the included cargo straps through the anchor points and pull the straps tight to secure your gear.

629806 Thule Motion XT XL Roof Top Cargo Carrier - 18 cu ft - Black

Replaces Thule TH6298B and TH635B

Installation Details TH629806 Installation instructions

Customer Satisfaction Score:

Customer Reviews

Thule Motion XT Rooftop Cargo Box - 18 cu ft - Black Glossy - TH629806

Average Customer Rating:  4.8 out of 5 stars   (475 Customer Reviews)

84-1/2 x 36 x 17. Roof box mounts to your crossbars with PowerClick clamps. Locking lid opens from either side of your vehicle. Great for carrying skis, snowboards, and other gear on crossovers and mid-size wagons. Durable ABS plastic construction.


The box is big (XL), shiny and sleek. Looks great on our 2021 Subaru Ascent. It weighs about 40lbs, so I was able to simply lift it up and onto the stock Subaru cross bars by myself with a bit of effort going towards balance. Then it was just a matter of attaching the clamps by hand tightening them. I don’t think it could get any easier. The locking mechanism is very assertive and secure. The box is big and can hold just about anything you’d need on a road trip. However, on a midsize SUV like the Ascent, it seems like the perfect size, not too small, not too big. It’s a good fit. Unfortunately, my small 2 car garage is too low to accommodate the vehicle with the box in place. Overall it’s a very refined and well thought out package.

One year later, the box is still functioning as expected. I’ve come to appreciate the rugged, yet sleek aesthetics. They really allow this box to stand out against the completion. My advice to new buyers would be to buy as much box that will fit on top of your vehicle. You’ll find that you’ll always be wanting more space.
Chris - 05/06/2022


Easy to install on load bars and easy to use. Either-side access mechanism works well. Not noisy at speed and doesn't block radio signals to shark-fin antenna. Not very heavy, but too bulky for easy one-person handling. What I least like is that instructions require flat storage (I assume to prevent distorting the plastic enclosure).


Really well built cargo box that was easier than I expected to attach to the rails on my car! Looks great on a Tesla Model Y.


Easy install and delivery was earlier than expected. Install was straight forward and I was able to install it by myself. Thule Motion XT XL.


Perfectly fits my Tesla Model Y. Have used on thousands of miles of road trips. To maximize space recommend Thule duffel bags.


Fits great on a 2022 MDX.
Great to pair
with the Thule ceiling mount. Easy enough for kid to lower!


Fits GREAT on my 2019 Honda Passport and was super easy to install. I love the sliding mounting brackets -- that made it really easy to get it positioned where I wanted it. The back hatch still opens all the way and even wound up with a little room to spare on the front. This box is super high quality. The lock and latches feel really solid, it opens very smoothly, and it looks great!


Everything arrived quickly and not damaged. Install was easy enough. Test drive with it on had no problems. Customer service was good and I appreciate all of the informative videos you make.


Thule box is a great product and well made. Access from either side is perfect. We piled in 5 skis, 1 snowboard, and most of our ski pants and jackets for our 25+ hour ride to Colorado. The etrailer team was great to work with on our purchase.


Perfect for road trips. Somewhat easy install with platform stand.


Mine arrived yesterday (about 12 days behind schedule due to several severe weather storms) and it's already installed on my car. Was super easy to install (I did it by myself and I am 20 weeks pregnant). It already had all off or skis loaded in it and ready for a trip to the mountains. etrailer was easy to work with and very responsive. Can't wait for them upcoming adventures!


Ordered a Thule Motion XT XL. Was promptly shipped via LTL by etrailer. Cargo carrier arrived in great condition banded to a pallet. We love the XT XL and it is the perfect size for our 2016 Cadillac Escalade (non-esv). We thought about going with the XXL, but glad we didn't, because the back hatch would have likely made contact with an XXL box. Using factory mounting points for rails, the XL fits like a glove. The motion series features and aesthetics are worth the extra price. Etrailer always has the best prices and shipping on these larger items.


Thule arrived with a bad strut, etrailer had a new one in my hands in a couple of days!

Clicked it in easily and am extremely happy with results ... see photo.


Replaced an older model Thule cargo box with this one. Fantastic upgrade. More space with an even slimmer profile somehow. Clamping mechanism for rack is much improved as are the hinges and lock. Quiet and solid on the road.


Perfect fit for my Forester and exactly what I was looking for. Solid mount and a fantastic looking piece of kit. Definitely worth the price and I will definitely be using etrailer again.


Great box. Used for 1000 mile trip with no problems. Almost no wind noise, the small amount there was was in excess of 65 mph. It’s on a 2020 Jeep Grand Cherokee limited, the lift gate will hit the back of the box if you let it open all the way, rigged up a string with two hooks to hold the gate off of the left gate.


The package arrived in great condition. The package contents were well padded and protected. The cargo box was easy to install on the existing roof racks. The box is large enough to hold plenty of cargo. However, the key locking/unlocking mechanism has much room for improvement, as the key is challenging to insert into the keyhole.


Thule cargo box arrived with no damage as it was packaged really well from etrailer. Thank you


With last year’s ski season being quite different due to COVID,I wanted to use my car as my lodge. One issue was where to put the skis in the car. I ordered up this Thule and it became my trunk, freeing up the rest of my car for me to make into my lodge. The box stayed on top all winter and I left the skis in there, feeling super secure because of the locking mechanisms. When it came time to take it off, I was able to do it single handed. The clamp/release mechanisms are superb. And I appreciate the ability to access the contents from either side. This summer I loaned it to a friend who used it for 4 golf bags on an extended golf trip. I love this thing.


Great cargo box. Easy to attach to your existing roof bars (once you have gotten on top of the car!).


This rooftop box was perfect for our long road trip. We are a family of four and the Thule Motion XT was easy to install, and held everything easily. It looks great on the car and never budged even in high winds, and kept everything dry during a heavy rain storm. Also it was very quiet and didn't rattle or slow the car down in any way. I am very pleased with this purchase!


Service and delivery from eTrailer was top notch as always. The product was accuratley described and I think it is true of all toppers now but I am not impreseed with opening and closing the system. The top does not open smoothly, (rachets back and forth). I would recommended buying a less expensive unit as I don't think you get much more for paying extra for Thule

I used it on a 15 state, 6,000 trip so I did thoroughly test it.


Love the cargo box. The customer service went above and beyond to resolve a small shipping issue. Would recommend.


Works great. Although I have put it on the car by myself a few times, I find it is easier for 2 people to put it on the car. Once on, it works well although some care is required to open the box.

I don't even notice it while driving.


A big cargo box! We love it!

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Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Jameson C
Expert Research:
Jameson C
Employee Andrew K
Video by:
Andrew K
Employee Chris R
Video by:
Chris R
Employee Jacob T
Video Edited:
Jacob T
Employee Dustin K
Video Edited:
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Employee Colin H
Installed by:
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Employee Wilson B
Updated by:
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Employee Carrie F
Updated by:
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Employee Matthew S
Written by:
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Employee Daron K
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Employee Adam E
Test Fit:
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