Thule 635S Sonic XL Silver

Thule 635S Sonic XL Silver
  • Thule 635S Sonic XL Silver Alternate Image Thumbnail
  • Thule 635S Sonic XL Silver Alternate Image Thumbnail

Product Code: 100635S

Status: Discontinued
"The folks at Rack Attack are true experts in this category."
- Fred Clark, CEO Thule
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The Thule Sonic Box combines efficiency with style. It's designed for those looking for an aerodynamic box with a wide variety of sizes and convenience options. The Thule 635S Sonic XL Silver has a 17 cu.ft. cargo capacity.


  • 17 cubic feet cargo carrying capacity
  • High-gloss automotive finish
  • Patented AeroNose design cuts through the air and reduces drag and noise
  • Patented rear-angled base and expanded vehicle mounting points help maximize trunk and hatch clearance
  • AcuTight mounting "clicks" when you reach optimal hold to ensure your box is secured to the rack
  • Oversized SecureLock ensures the box is closed securely and properly prior to driving
  • Dual-side opening for loading/unloading from either side of the vehicle
  • Fits Thule rack systems, round bars and most factory racks
  • Dimensions: 89" x 34" x 16"

Buying Notes

The Thule Sonic will ship directly from Thule, please allow 7 - 14 <b>business days</b> for delivery.


Weight: 47lbs

Length (carton): 89"

Width (carton): 34"

Height (carton): 16"

UPC: 091021373426

Manufacturer: Thule

Manufacturer Part Number: 635S

Thule Warranty

Thule warranty information.

Thule Warranty

Ask A Tech if This Rack Fits Your Car

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Your Review


Vehicle Select


The entire experience was totally painless. The RackAttack folks were more than helpful. I was very impressed with the speed in shipment. The 635 Sonic XL is a snap to install / remove. I'm transporting multilple rods and reels in this cargo box and it has plenty of room to spare. I'd suggest to anyone getting this cargo box for a higher profile vehicle, to consider the step that fits over the tire. This folding step is plenty stout, and makes accessing the cargo in the box a breeze. Thule and Rack Attack seem to make a wonderful combination.

2000 Ford / Leer F-150


Shipping was incredibly fast on this item. This item was purchased to transport large numbers of different types of rods/reels via cargo carrier. Seems very sturdy and capable of it's purpose. Mounting system is very easy and convenient to install /remove, but secure as long as lid is closed/ locked. The purchase of this item from RackAttack was as easy as any that I have made. I'd certainly recommend purchasing the step for accessing this cargo box and it's contents. Still waiting on the road trip to fill this box to capacity, but you can tell by it's design that great trouble was taken in design to make this carrier aerodynamic as well as quiet.

2000 Ford F-150 / LEER CAP


Frequently Asked Questions

Below you will find a list of the most frequently asked questions for this product. If you need more assistance you can email a rack-install technician, or call us at: 1-888-440-5556

While the weight limit of your roof rack may differ, cargo boxes can hold up to 165 pounds.

While you will want to take some measurements of your bag, any of the Thule XL (or XXL) boxes would be would be a great pick. XL size Thule boxes have 17 cubic feet of space and about 17 inches of height depending on the box. Just make sure to measure the distance from your rear roof bar to your open hatch (if you have one) to make sure it will clear. If you have any questions on that call or email us at Rack Attack.

As long as your vehicle is equipt with the crossbars (side to side) then all of our cargo boxes will attach directly to the rack. If you have a rear hatch, make sure to measure how much room you have and compare to the box length to make sure the hatch won't hit the box when opening. If you don't have crossbars, you will first need to add those prior to adding in a cargo box.

If you drive an SUV or van, probably not. Be sure to measure the total height of the vehicle with the Thule 635S Sonic XL Silver installed, and keep that information handy (on the inside of your sun visor is a great place). Running into your garage will, unfortunately, void the box's warranty.

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