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Thule Sidekick Roof Mounted Cargo Carrier Box - U-Bolt Mounts - 8 Cubic Feet

Thule Sidekick Roof Mounted Cargo Carrier Box - U-Bolt Mounts - 8 Cubic Feet

Item # TH78GC
Our Price: $499.95
You Save: $37.86
Roof Box
Shipping Weight: 21 lbs
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54 x 25 x 15. Roof box mounts to your crossbars with U-bolts and reinforcement plates. Locking lid opens from the passenger's side of your vehicle. Great for carrying luggage, groceries, and other gear. Impact-resistant polyethylene construction. Great Prices for the best roof box from Thule. Thule Sidekick Roof Mounted Cargo Carrier Box - U-Bolt Mounts - 8 Cubic Feet part number TH78GC can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (32)
  • Q & A (0)
  • Photos

Thule Roof Box - TH78GC

  • Aero Bars
  • Elliptical Bars
  • Factory Bars
  • Round Bars
  • Square Bars
  • Extra Small Capacity
  • Thule
  • Short Length
  • Black
  • Medium Profile
  • Passenger Side Access

54 x 25 x 15. Roof box mounts to your crossbars with U-bolts and reinforcement plates. Locking lid opens from the passenger's side of your vehicle. Great for carrying luggage, groceries, and other gear. Impact-resistant polyethylene construction.


  • Cargo box mounts on your vehicle's roof rack to provide enclosed storage for your gear
  • Lid opens from the passenger's side for safety and convenience
  • Included lock helps deter theft
  • Aerodynamic design reduces wind resistance
  • Impact resistant, polyethylene construction ensures durability
  • Weather-resistant design helps keep cargo dry
  • Attaches to crossbars with included U-bolts with reinforcement plates


  • Application: round, square, aero, elliptical, and most factory crossbars
    • Maximum crossbar diameter: 3-3/4"
    • Crossbar spread: 23-5/8" - 28"
  • Carrying capacity: 8 cu ft
    • Height above crossbars: 15-1/2"
  • Weight capacity: 75 lbs
  • Dimensions:
    • External: 54" long x 25" wide x 15-1/2" high
    • Internal: 48" long x 23" wide x 13-1/2" high
  • Weight: 20 lbs
  • Limited lifetime warranty

Sidekick Fit Diagram

682100 Thule Sidekick Roof Mounted Cargo Carrier Box - U-Bolt Mounts - 8 Cubic Feet

Replaces Thule 682

Installation Details TH78GC Installation instructions

Customer Satisfaction Score:

Customer Reviews

Thule Sidekick Roof Mounted Cargo Carrier Box - U-Bolt Mounts - 8 Cubic Feet - TH78GC

Average Customer Rating:  4.6 out of 5 stars   (32 Customer Reviews)

54 x 25 x 15. Roof box mounts to your crossbars with U-bolts and reinforcement plates. Locking lid opens from the passenger's side of your vehicle. Great for carrying luggage, groceries, and other gear. Impact-resistant polyethylene construction.


I have been really happy with this roof box, I was concerned at first because it did not feel as heavy or sturdy as some I've had in the past but it's performed really well and the shape is great. Because of the shape it holds things like carry on luggage on their side, backpacks and lots of gear. A year in, still loving this purchase.


This review is not about the Thule Sidekick I ordered. It is about etrailer. Their prices are very competitive and I received free shipping. I placed my order on a Friday, was promised delivery the following Thursday and my item was delivered two days earlier on Tuesday. I will certainly consider etrailer for future purchases.



No complaints, the Sidekick is a lower end cargo carrier but that is reflected in the price and it suits my needs just fine.


This cargo carrier is perfect for our needs. Stacey with etrailer helped with ordering & any questions we had. The topper arrived quickly, we didn’t install immediately waiting on roof rack rails.
A week or so later ready to install we noticed a rivet missing on the front lock… took pictures & emailed Stacey. She called back within hours & the next day a replacement was on the way…..

We’d give 10 stars for her exceptional Customer Service! Thank you for exceeding our expectations!


I have a 2016 ford focus se hatchback & I mounted this in the middle on rhino rack vortex bars. Looks awesome! It’s very sturdy & I can fit a decent amount in this box.


Quick delivery. We just put together the box, haven't used it yet, but everything looks good.



Works great. Weve used it a half a dozen times, and it has worked well each time.


The sidekick has been a great cargo box for road trips over the last year.


This is a great addition to my Subaru Forester for camping and outdoor adventures! It holds up really well even during a rainstorm. Very happy to have purchased it.


Got Very Frustrated on step one as Paper kept sticking to foam sealer, until I cut back nearly 12" of material!
Directions are MINIMALLY Clear. Luckily I am an Engineer and got lucky via deductive reasoning


We've used a few times for long trips with 5 kids and 2 adults. It definitely gave us the cargo space we needed for the trip.


It works great. Easy enough to put together and install/remove from the car. We were torn between this and slightly bigger model. Could have went bigger, but this freed a lot of space and made packing Tetris much easier.


This was a game changer! We have started making trips from TX to NC and NC to FL several times a year. After getting 2 adults, 2 teens and 2 dogs in my Lexus NX, there's not much room inside the car for much. Getting this Thule roof rack box has been great. Amazing how much stuff and then some will fit. Minimal noise and insignificant impact on mpg too. Great purchase.


Meets its needs. Plastic is rather thin - definitely meant to haul lighter items, but is rather spacious for its compact length. Requires some assembly with two people. Spouse is happy because it fits some extra beach gear she wanted to haul on vacation.


Like the product, good quality, easy as sembly


It’s been great overall, but the key did break in one of the locks which has been inconvenient.


Thank you for shipping so quick. I received it in 2 days.


product arrived on time and in excellent condition.


Delivered Thule rooftop box on time in excellent condition.


It arrived a bit banged up. There were a number of dents probably related to being banked around during shipping. Most popped out. One or two may not. I haven’t put it together, so maybe they’ll relieve. We’ll see

Etrailer Expert

Jenny N.


I appreciate that you have popped out the dents however I will have our customer service team reach out to assist you.


From purchase to delivery, etrailer was amazing. Thanks for making everything easy.


Was a great fit for the Tacoma SX model.



Etrailer Expert

Heather A.


Wow! I am sorry you had a bad experience with the cargo box. Thule is one of our most trusted brands so forgive me if I sound surprised. Can you give me more information about why the box is crappy? I am happy to help!


Looks nice


One of the hinges were broken when I received the item


Perfect! Just what we were hoping for.


Show More Reviews

See what our Experts say about this Thule Roof Box

  • Will Thule Sidekick Fit Roof Rack Installed on 2009 Honda CR-V
    I did receive your picture and I confirmed with Thule that it is not a Thule roof rack that's been installed on your 2009 Honda CR-V. However, the Thule Sidekick # TH78GC may still work for you. To find out for sure you can measure the crossbars. As long as they are no more than 3-3/4 inches wide the Sidekick will fit. It's designed for aero shaped bars like you have. Another good measurement to take is from the center of the front crossbar back to the antenna. You'll need at least...
    view full answer...
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  • Can Thule Sidekick Roof Mounted Cargo Carrier Box be Mounted Offset on Roof Rack
    Yes, you can offset the Thule Sidekick Roof Mounted Cargo Carrier Box # TH78GC as opposed to mounting it directly in the center of the crossbars on your 2021 Kia Telluride. This opens up to the passenger side of the vehicle so I recommend mounting it closer to the passenger side of your vehicle so you aren't having to reach as far to gain access to the inside of the box.
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  • How to Help Secure the Cargo Inside of the Thule Sidekick Roof Mounted Cargo Carrier
    The Thule Sidekick Roof Mounted Cargo Carrier Box # TH78GC does not have any built-in mounting points inside of the carrier. The best way to help secure the cargo inside of the box would be to overpack the box. Use things like towels and blankets to add depth and padding for the cargo and fill in empty spaces to prevent as much movement.
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  • Reducing Wobbling on a Thule Excursion Roof Top Box
    There are a few things that you can do to ensure a fit, and approach the wobble of your existing box without making a purchase. First, you'll want to make sure that your crossbar kit is spread out as far as the mounting system or crossbars will allow. This will give the roof box a better platform to rest on while driving, and reduce its wobble. Next, when you load the roof box, you'll want to make sure that less of the weight is put into the front of the box, and put more into the middle...
    view full answer...
  • How to Determine if Thule Sidekick Cargo Box Will Fit Roof Rack
    You didn't mention the specific model 2015 Toyota that you have but if the bars are between 23-5/8" - 28" and are less than 3-3/4 inches in diameter the Thule Sidekick part # TH78GC will fit it and work well. Dimensions: External: 54" long x 25" wide x 15-1/2" high Internal: 50" long x 23" wide x 13-1/2" high
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  • Availability of Roof Mounted Cargo Box to Fit Inside a 60 by 50 Inch Cargo Basket
    Given that amount of space you have to work with, I'd recommend going with the Thule Sidekick you looked at, part # TH78GC. The cargo box measures 54 x 25 inches, which would fit nicely in your cargo basket. The basket mounts using U-bolts, so you'd need to make sure that the bottom of the basket has lateral bars for the box to mount to that are between 23-5/8 and 28 inches apart. Width wise, the box would take up about 1/2 the basket leaving about 12 inches of space on either side of the...
    view full answer...
  • Thule Roof Box for a 2016 Toyota 4Runner with Factory Roof Rack and Crossbars
    I have a solution for you, but unfortunately, neither the Thule Force XXL or the Thule Motion XT will fit the 2016 Toyota 4Runner equipped with factory crossbars and allow you to operate the rear hatch. I instead recommend the Thule Sidekick, part # TH78GC, which is an efficient, easy to use box that will fit the factory bars.
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  • Replacement Side Hinge For Thule Sidekick Roof Mounted Cargo Box
    I spoke to my contact at Thule and they told me the hinge for the Thule Sidekick Cargo Box is not an item that is sold as a separate item. You may want to remove the hinge and take it to a local hardware store. Most stores have door hinges that are very similar and may have just what you are looking for.
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  • Recommended Cargo Box for a 2013 Toyota Highlander with Factory Rack
    I checked with a few of the major cargo box manufactures, Thule/Yakima and only found one compatible option which is the Thule Sidekick Roof Mounted Cargo Carrier Box part # TH78GC. This cargo box has a 8 cu. ft. capacity which is still plenty to free up some space inside the vehicle. It has locks for security and is one of the more cost effective options on the market.
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  • How to Mount Karrite Voyager Cargo Box to Roof Rack
    The Karrite Voyager was a distant relative to the current Thule Sidekick Cargo Box # TH78GC. The box uses standard U-bolt hardware to attach to roof rack crossbars and tightens down with the included plates and threaded knobs. I have attached the complete installation instructions for the Thule Sidekick that you can take a look at, along with an image that clarfies where each piece of the hardware goes. The process will be identical on your Karrite Voyager.
    view full answer...
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  • How Does the Thule Sidekick Install on Crossbars
    If you were near St. Louis, MO you could come out and we would be happy to install the # TH78GC for you. It's really not too hard to install. For the most part you would just need to set the box on the crossbars of your vehicle and then run the included u-bolts up around the crossbars and then through the box using the included wing nuts to tighten them. To make it easier to get up high enough to install the box you may be interested in the tire step part # HE4040.
    view full answer...
  • Will the Thule Motion XT Alpine Cargo Box Fit a 2019 Subaru Impreza With Factory Crossbars
    It looks like you've already done all the measuring you need, so the Thule Motion XT Alpine Rooftop Cargo Box # TH629506 will work just fine with your 2019 Subaru Impreza. This cargo box only requires that you have a minimum crossbar spread of 23 5/8" but no more than 36 7/8" apart. Since you have a maximum crossbar spread of 33" you're good since you're within those parameters. If you have the hatchback and want to be able to open the hatch without interference you'd need to make sure...
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  • Recommended Roof Top Carrier for 2014 Toyota RAV4 XLE
    I am going to assume that your 2014 Toyota RAV4 XLE is already equipped with a roof rack. In order to make a recommendation for a roof top carrier I will need to know the type of crossbars used for your roof rack system, the minimum and maximum crossbar spread, and the front clearance measurement. The front clearance measurement is the distance from the center of the front crossbar (if adjustable, slid as far forward as possible) to the seam between the roof and hatch. The Thule Sidekick,...
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  • Does the Thule Sidekick Have Hinges, Locks, and a Seal
    The Thule Sidekick Roof Mounted Cargo Carrier Box # TH78GC does use a combination of hinges and struts to easily raise and lower the lid. It includes locks to deter theft of your gear and although there isn't a "seal", there is a foam gasket included to help keep your gear safe from the elements.
    view full answer...
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  • Is the Thule Sidekick Compatible with Round Bars
    The Thule Sidekick Roof Mounted Cargo Carrier Box, part # TH78GC, is in fact compatible with round bars as is. You do not need an adapter for this to work for you. I've linked to a video review of the Sidekick below.
    view full answer...
  • Recommendation to Transport 185 cm Skis on 2016 Toyota 4Runner with Factory Roof Rack
    The only roof cargo box we have available that is confirmed to fit the factory crossbars on your 2016 Toyota 4Runner is the Thule Sidekick Roof Mounted Cargo Box # TH78GC. This is likely due to the extremely low profile design for the factory crossbars on this vehicle, as only cargo boxes that use a U-bolt attachment system will fit. This particular cargo box features 8 cubic feet of space and will not be large enough to store your skis. To transport your skis using the factory roof rack...
    view full answer...
  • Can I Purchase the Thule Sidekick Mounting Screws, Screw Covers, Washers, and Nuts Individually?
    While we do have the mounting screws, screw covers, washers, and nuts for the Thule Sidekick Cargo Box # TH78GC, they only come in the kit # TH04958 that includes the rest of the hardware. I confirmed with the Thule schematics for the Sidekick that this hardware collection is the only hardware set available for the box.
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  • Is the Thule Sidekick Roof Top Cargo Box Waterproof
    The Thule Sidekick Cargo Box # TH78GC is designed in such a way to help keep water from the road and elements out and off of your gear. However, with that being said, it is not waterproof. There's always a chance water can get inside the box and on your things. So if you're carrying something that absolutely cannot get wet I recommend sealing it in some sort of bag and then put it in a cargo box or carrying it inside the vehicle.
    view full answer...
  • Small Cargo Box Recommendation for a 2014 Honda Pilot with Factory Crossbars
    I wish I had a solution for you that I could provide that would allow your box to fit the rack of your vehicle, but the only replacement hardware kit I can recommend for the Weekender is part # TH04997 which would be exactly what you already have. The only real solution I could provide would be to upgrade to a new box that can fit the crossbars you have like the Thule Sidekick # TH78GC that has been confirmed to fit your vehicle. Check out the review video I attached as well.
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  • Cargo Box Recommendation for a 2013 Cadillac SRX Factory Crossbars
    I checked with Thule and they list their Sidekick part # TH78GC as a fit for the factory crossbars of your 2013 Cadillac SRX so it would work well for you.
    view full answer...
  • Replacement Mounting Hardware Needed for Thule Sidekick Cargo Box # TH78GC
    For the full hardware mounting kit for your Thule Sidekick Cargo Box # TH78GC, that is the Replacement Mounting Kit for Thule Sidekick Cargo Box # TH04958. This kit comes with everything you need and includes the following: - 4 U-Bolts - 8 Knobs - 4 Backing Plates - Vinyl stripping - Circles - 2 locks and 2 keys - Mounting screws, screw covers, washers and nuts
    view full answer...
  • Roof Cargo Box Compatible with OEM Roof Rack on a 2015 Toyota 4Runner Limited
    The only cargo box that has been verified to fit your 2015 Toyota 4Runner Limited OEM roof rack is the Thule Sidekick # TH78GC. All of the other options basically say there isn't enough room for the mounting hardware. If you want/need to use something larger then we need to get you an aftermarket roof rack system. If you'd like to upgrade your crossbar system just let me know and I'll be happy to make some recommendations for you, otherwise have fun with the Sidekick! I've attached a review...
    view full answer...
  • Does the Thule Sidekick Cargo Box Have to be Centered on the Cross Bars of a Roof Rack
    You can mount the Thule Sidekick to one side or the other when installing it on a roof rack cross bar. We recommend you put it closer to the passenger side so that if you were on the side of the road you would be on the side of your vehicle that would be on the opposite side of traffic.
    view full answer...

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Info for this part was:

Employee Andrew K
Installed by:
Andrew K
Employee Jameson C
Expert Research:
Jameson C
Employee Chris R
Video Edited:
Chris R
Employee Wilson B
Updated by:
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Employee Matthew S
Written by:
Matthew S
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Video by:
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