If you want a proven, lightweight system with a sleek profile that feels engineered for daily reliability, choose Thule Force 3; if you need massive storage volume and hydraulic-assisted access for a family road trip, choose SierraSquad ABS Rooftop Cargo.
• Thule Force 3: Strengths include a rugged, streamlined design tested in extreme conditions and an intuitive mounting click-system; the trade-off is its lower total cubic capacity compared to larger competitors. This pick is for the active driver who prioritizes aerodynamics and brand heritage over sheer bulk.
• SierraSquad ABS Rooftop Cargo: Strengths lie in its colossal 600L–880L storage options, dual-side opening with hydraulic arms, and waterproof sealing for harsh weather; the trade-off is its heavier build and slightly larger footprint on the roof rack. This pick is for the pet owner or large family needing to haul strollers, camping gear, and multiple suitcases without sacrificing cabin space.
The Thule Force 3 XL is built for the driver who views their cargo box as an extension of their vehicle's performance rather than just a storage bin. Its defining characteristic is the balance between durability and a low-profile aesthetic. The manufacturer has extensively tested this unit at their own Test Center, ensuring it can handle the rigors of daily use and demanding active lifestyles without compromising the car's handling or fuel efficiency. If you are someone who drives frequently and wants a box that disappears into the background while still offering robust protection, this is the direction to go.
One of the most practical features for any user is the SlideLock system. It separates the locking mechanism from the opening function, which automatically secures the lid when closed and provides a clear indication that the box is safely attached. You do not have to guess if your gear is secure; the simple click tells you it is locked down tight. This level of mechanical precision suggests a design philosophy focused on safety and ease of use, allowing you to load up quickly before hitting the highway.
However, you should skip this option if your primary goal is maximizing every single cubic inch of available space. While the dimensions are substantial at roughly 84.8 inches in length, the overall volume is designed for efficiency rather than excess. It is ideal for skis, snowboards, or a moderate amount of luggage, but it lacks the cavernous interior required for families packing for week-long vacations. If you are looking for a box that can swallow a folding stroller and six large suitcases simultaneously without leaving room to spare, the Force 3 might feel too compact for your specific needs.
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-11-05 · 5 min read · Independent comparison
The SierraSquad ABS Rooftop Cargo Box is clearly engineered for the heavy lifter. Whether you are transporting pets, children, or a household full of camping equipment, this box is designed to solve the problem of limited trunk space head-on. With options ranging from 600L to a massive 880L, the largest model can hold six or more large pieces of luggage. This makes it an exceptional choice for families where the back seat is already occupied by kids or pets, forcing you to move all the gear to the roof. The sheer capacity ensures that bulky items like tents, sleeping bags, and oversized suitcases have a dedicated home, keeping the interior of your SUV or sedan clear and comfortable.
Accessibility is another major selling point for this unit, particularly for those who park in tight spaces. The dual-side opening feature allows you to access your belongings from either side of the vehicle, meaning you never have to walk around the entire car to grab a jacket or a water bottle. The hydraulic support arms are a standout detail here; they lift the lid with one hand and hold it open securely, eliminating the struggle of propping up a heavy lid against gravity. This convenience factor is significant when you are unloading after a long drive or trying to organize gear at a campsite in the rain.
Durability and weather protection are central to the SierraSquad design. The hard ABS case is sealed tightly to protect contents from rain, dirt, and strong sunlight. For owners who take their vehicles off-road or live in areas with unpredictable weather, knowing that clothes and sleeping bags will stay dry even in snowy or breezy conditions is invaluable. The streamlined, water-drop shape also helps reduce wind resistance and noise at highway speeds, addressing the common complaint that rooftop boxes are noisy and inefficient.
• Best for Maximum Storage Volume → SierraSquad ABS Rooftop Cargo (Up to 880L capacity vs. standard Thule sizing)
• Best for Aerodynamic Efficiency → Thule Force 3 (Streamlined design tested for minimal drag)
• Best for One-Handed Access → SierraSquad ABS Rooftop Cargo (Hydraulic arms hold the lid open automatically)
• Best for Dual-Side Convenience → SierraSquad ABS Rooftop Cargo (Opens from left or right without repositioning)
• Best for Proven Daily Durability → Thule Force 3 (Extensively tested in controlled environments for rugged reliability)
• Best for Security Integration → Thule Force 3 (SlideLock system with separate locking and opening functions)
• Best for Weather Sealing → SierraSquad ABS Rooftop Cargo (Tightly fitted seals specifically marketed for waterproof and sun-resistant travel)
• Best for Pet Owners Needing Space → SierraSquad ABS Rooftop Cargo (Holds extra gear for animals and families without crowding the cabin)
After weighing the specifications and real-world applications, I would personally buy the SierraSquad ABS Rooftop Cargo if my primary concern was hauling gear for a large family or frequent pet travel. The ability to store six large suitcases or a stroller while keeping the interior quiet and spacious is a game-changer for road trips. The hydraulic arms and dual-side access make the daily loading process significantly less frustrating than wrestling with a standard lid. However, if you are a solo traveler or a couple who values a sleeker profile and doesn't need to carry mountains of luggage, the Thule Force 3 remains a superior choice for its refined engineering and lower weight. For the pet owner who needs to transport crates, toys, and supplies alongside their family, the SierraSquad offers the necessary utility that the smaller box simply cannot match.
According to the product details, the SlideLock system automatically locks the lid in place and indicates when the box is closed securely, separating the locking function from the opening mechanism.
Yes, the SierraSquad features a dual-side opening design that allows you to lift the lid and access your belongings from either the driver or passenger side of the vehicle.
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