Difference Between Thule Force XT & Thule Motion XT Cargo Boxes

Updated 03/31/2022 | Published 03/30/2022

Question:

I have a Mercedes 2019 GLS450 SUV. Considering buying Thule rooftop carrier but I have 2 questions: 1 Cant decide between the Thule Motion XT vs. Thule Force XT. Which is better? The Motion is more expensive, but why? 2 Which is more fitting for my GLS450: the XL 18 cubic feet or the XXL 22 cubic ft model? Would the XXL model restrict the opening of my SUVs liftgate? Thanks.

asked by: Calvin

Expert Reply:

So there are really only a pair of differences at base between the Thule Motion XT and Thule Force XT rooftop cargo boxes. One is the aesthetic, with the Force XT having a textured, flat black finish, while the Motion XT has a high-gloss black finish. Which one you like more comes down to personal preference as there isn't an advantage to having one over the other.

The other difference is the locking system; the Motion XT has what Thule calls a SlideLock system that automatically locks the lid when you close it. The Force XT has locks as well, but you need to use the key each time you want to lock the box. In regards to the price difference, I don't have the answer to that, but I assume it's just the number Thule decided on based on their research.

As for allowing your rear hatch to open, we haven't test fit them on a 2019 Mercedes GLS450 to know if it will be able to with either box, but it's pretty easy to find out. All you have to do is measure from the center of your front crossbar to the seam where your rear hatch opens. If you measure and get MORE than the numbers listed below, you will be able to open your hatch.

- 51-1/8 Inches: Thule Force XT XL Rooftop Cargo Box - 18 cu ft # TH6358B

- 51-1/4 Inches: Thule Motion XT XL Rooftop Cargo Box - 18 cu ft # TH629806

- 54-3/4 Inches: Thule Force XT XXL Rooftop Cargo Box - 22 cu ft # TH6359B

expert reply by: Kyle S