bing tracking image
  1. Roof Box
  2. Thule
  3. Aero Bars
  4. Factory Bars
  5. Square Bars
  6. Round Bars
  7. Elliptical Bars
Thule Force XT XL Rooftop Cargo Box - 18 cu ft - Black AeroSkin

Thule Force XT XL Rooftop Cargo Box - 18 cu ft - Black AeroSkin

Item # TH6358B
Our Price: $799.95
You Save: $350.17
Roof Box
This item qualifies for Free Truck Freight Shipping
Shipping Weight: 50 lbs
In Stock
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

Customer Photos

Need help with installation?
Locate installers near me
82-3/4 x 33-3/4 x 17-1/4. This aerodynamic, low-profile cargo box holds outdoor equipment and large luggage for up to 5 people. Quick-Grip clamps let you quickly mount the box to your roof rack, and the locking lid opens from both sides. Great Prices for the best roof box from Thule. Thule Force XT XL Rooftop Cargo Box - 18 cu ft - Black AeroSkin part number TH6358B can be ordered online at or call 1-800-940-8924 for expert service.
  • All Info
  • Reviews (241)
  • Q & A (0)
  • Photos
  • Used (1)
  • Why etrailer?

Thule Roof Box - TH6358B

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

82-3/4 x 33-3/4 x 17-1/4. This aerodynamic, low-profile cargo box holds outdoor equipment and large luggage for up to 5 people. Quick-Grip clamps let you quickly mount the box to your roof rack, and the locking lid opens from both sides.


  • Low-profile, roof-mounted cargo box provides enclosed storage for your gear
    • Perfect for outdoor equipment, large luggage and baby gear for up to 5 people
    • Great for mid-size wagons and crossovers
  • Pre-installed Quick-Grip mounting clamps provide 5-minute installation on your crossbars
    • Simply turn dials to secure mounting clamps to roof rack
    • Integrated PowerClick torque indicator clicks when clamps are properly tightened
  • Aerodynamic shape helps to reduce drag and wind noise
  • Dual-side-opening lid lets you load and unload gear from either side of your vehicle
    • Hand knob on lock makes lid easy to lift and close
  • Oversize SecureLocks ensure that lid is closed and locked
    • Key can only be removed when box is properly closed and locked
    • 2 Thule One-Key System locks included
  • 2 Load straps connect to built-in anchor points on Quick-Grip hardware to secure your gear
  • Rugged ABS plastic construction resists impacts, weather and harsh UV rays
  • Black AeroSkin diamond-texture lid and base looks stylish on your roof
  • Made in the USA


  • Application: round, square, aero, elliptical, and most factory crossbars
  • Maximum crossbar dimensions: 3-1/2" wide x 1-11/16" tall
  • Crossbar spread: 23-5/8" - 35-7/8"
  • Carrying capacity: 18 cu ft
  • Weight capacity: 165 lbs
  • Hatch clearance: 51-1/8"
  • Ski/snowboard capacity: 5 - 7 pairs of skis or 3 - 5 snowboards
  • Maximum ski/snowboard length: 194 cm
  • Dimensions:
    • External: 82-3/4" long x 33-3/4" wide x 17-1/4" tall
    • Internal: 77-1/2" long x 29-1/2" wide x 15-1/4" tall
  • Box weight: 47 lbs
  • Limited lifetime warranty

Cargo Box Clearance Dimensions

635801 Thule Force XT Extra-large Roof Mounted Cargo Carrier - 18 cu ft - Black AeroSkin

Replaces Thule TH625 and TH6358B

Installation Details TH6358B Installation instructions

Customer Satisfaction Score:

Customer Reviews

Thule Force XT XL Rooftop Cargo Box - 18 cu ft - Black AeroSkin - TH6358B

Average Customer Rating:  4.8 out of 5 stars   (241 Customer Reviews)

82-3/4 x 33-3/4 x 17-1/4. This aerodynamic, low-profile cargo box holds outdoor equipment and large luggage for up to 5 people. Quick-Grip clamps let you quickly mount the box to your roof rack, and the locking lid opens from both sides.


I’ve been owning this cargo box for over a year now , I love it and never had problems at all or any issues . Handles in weathers, power washing and high speed winds . Very sturdy and good looking cargo box


We just came back from a 2000+ mile trip from Maryland to the Gulf Shores. This cargo box worked flawlessly. The extra 18 cu ft of storage contained 3 carryon bags, 1 large suitcase, fishing gear, a small tent and an acoustic guitar. Had initially ordered the Yakima Grand Tour but it was backordered till next year. etrailer was able to provide other options and after comparing 6 boxes, this box was selected for its larger capacity, dimensions, price and aesthetics (it looks like an escape pod for some spacecraft). The length is longer than the Yakima but the frontal area (which is more important for range) is slightly lower and narrower. Mounting it on the factory crossbars was very easy. It takes only minutes to install or remove. The initial installation took the longest as I wanted to make sure it was centered before I marked the crossbars to make the next install easier. The box does flex a little on bumpy roads as we can see the front from our windshield but there were no issues driving in the low 80 mph range.


This cargo box fits well on our Toyota Sienna. It is lightweight but awkward for one-person handling. I would say that the hinge mechanism is novel and well designed. Due to the length and flexibility of the box itself, opening and closing can feel floppy before the box is secured to the roof.
We have only used this twice in the past year, on two 1,000 mile trips. One included a sustained, driving rainstorm. All of our luggage stayed dry. There is minimal wind noise. Due to much higher weight (passengers, luggage) and greater tire inflation, I can't quantify the fuel economy impact. Our Sienna averaged 25 mpg while driving 75 mph on the interstate.


The locking mechanism is VERY difficult to use, not sure if it is a defect with my box or a common problem. Also, you have to make sure it is aligned perfectly at three different points when closing, or the lock won't even engage. I have had to ask several strangers to assist me in locking/unlocking and loading up after a long ski day. Not user-friendly for one person.

I reached out to the manufacturer who will be in contact with you.
-- Etrailer Expert Jenny N - 03/17/2022


Another "made in the USA" quality packing failure. $[XX] flat pack furniture has better packaging protection than this $[XX] cargo box. The cargo box arrived in a loose-fitting thin cardboard box lick taped with one small piece of tape holding it closed (I think the shipper put it on to keep it closed). Several impact dents on the cargo box and a bent frame. The frame was not noticeable until after unlocking the cargo box. At least the cargo box was in a clear bag to keep it dust free. A little extra cardboard packing with foam would go a long way in protecting this item. I bought it new so would like it in new condition. Thule’s or etrailer’s packing department should expect rough handling while in shipment. All damage would have been preventable with the extra protection.


This is a larger roof box, but it fit just fine on our Subaru Forester. Holds a lot of gear for camping, and it's long enough to carry cross country skis too.


Remarkably easy to install - in less than five minutes. My wife and I easily lifted it in place, applied the attachments and were ready to go. Conveniently opens from either side. Able to adjust front to back and side to side to get to the optimal position on the roof rack. Even positioned as far to the rear as possible, the back gate of our Honda Odyssey opens with about two inches of clearance. Looking forward to our first loaded road test.

One year in and still loving it. Extra storage for a cross-country move, tents and sleeping bags, ski equipment, you name it-it fits. Easily handled skis, poles, boots and helmets for a family of six. No visible wear and tear and works as well as the first time. Definitely a good investment.
Mark - 07/23/2022


Do not buy this unless you want to spend 5mins+ every time you shut the lid. The locking mechanism is frustratingly horrible! On a positive note the available cargo space is amazing, it sits solid on the roof of my 4runner and it is impressively quiet on the highway. Unfortunately the difficulty in getting it to latch shut negates all of the positives.


With every single penny of it. The best. Very satisfied after owning it for a year.


Finally was able to use the box for Christmas. It worked very well and we took it off and put it back on during the vacation.
this is made much easier by being able to open the box on either side.


Outstanding service and overall great experience! Had to cancel one due to back order, switched it to the Force XT with no problems. Great experience!


The Rooftop Carrier has been everything we expected.


It was exactly as I had envisioned. I can’t wait to take it out on a trip to see if it performs as expected.


I ordered from etrailer because of price, price guarantee and product detail information was outstanding.


Works great - easy to install and remove, as needed.


A little more flimsy than I had hoped. I know, Thule is trying to save weight, okay. The clasp devices that holds the cargo box in place is worth the price. They are so easy to adjust and are very secure. Also, the ability to open the box from either side of the SUV is also worth the purchase price. Everything inside stayed dry in heavy rain. I really like the finish on the box. Good Product!


Made many road trips with this guy and it’s never leaked and never had any problems. Occasionally it’s hard to shut but that is more my fault for overloading it a bit.


It was heavily damaged in shipping and I had to return it for a refund.


THe product is great. It got here in time for our vacation

It has been great. Allowed us to get all the extra stuff out of the car until we need it. Easy to attach and remove.
Nancy - 08/17/2022


This Thule box has been great. It may not be the cheapest one out there but it's easy to install and all the mechanical functions are high quality. We have used this a number of times over the past year and I can store enough luggage in here for 5 people over the course of at least a week. Great for skis too.


Extremely satisfied with this product, exceeded my expectations.


Very happy! Exactly as shown. Great purchase and fantastic price. Never disappointed when I order from etrailer.


great response and quick shipping excel lent


Not many complaints. Great quality. Does what it is suppose to do.


easy install and very easy to open and shut. Love it. Only thing I did notice is one of the plugs was missing from the cap.

Show More Reviews

See what our Experts say about this Thule Roof Box

< Previous
123. . .12

Do you have a question about this Roof Box?

Used Items Available
Used Picture for Thule Force XT XL Rooftop Cargo Box - 18 cu ft - Black AeroSkin

Condition: Like New

Notes: May have damaged packaging or minor cosmetic blemishes.

Our Price: $750.95
Secure Checkout

  • Why

    At we guarantee:
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate roof box information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Employee Andrew K
Video by:
Andrew K
Employee Zach D
Video by:
Zach D
Employee Jonathan Y
Video by:
Jonathan Y
Employee Tyler C
Edited by:
Tyler C
Employee Jameson C
Expert Research:
Jameson C
Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video Edited:
Chris R
Employee Colin H
Test Fit:
Colin H
Employee Hayden R
Installed by:
Hayden R
Employee Wilson B
Updated by:
Wilson B
Employee Noah M
Updated by:
Noah M
Employee Carrie F
Updated by:
Carrie F
Employee Matthew S
Written by:
Matthew S

At we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.

Product Experts Available Now!
Call 1-800-940-8924