Dynamic vs Static Roof Load: What Rooftop Tent Buyers Need to Know

"My car's roof is only rated to 75 kg. The tent weighs 66.6 kg. How can two adults possibly sleep up there?" It's the question we hear most, and the answer comes down to two numbers that mean very different things: dynamic load and static load.

Dynamic load: what the roof carries while driving

The roof load rating in your vehicle handbook - typically 75 or 100 kg - is a dynamic rating. It's the maximum weight the roof and rack system should carry while the vehicle is moving, when cornering forces, braking, wind buffeting and corrugations multiply the effective load far beyond the object's resting weight. This is the number your tent (plus rack) must stay under. At 66.6 kg, the Roof Space 2 - the lightest hard-shell rooftop tent in its class - fits within a 75 kg dynamic rating on lightweight crossbars, which is exactly why it suits such a wide range of vehicles. Check yours on our car compatibility pages, like Toyota or Ford.

Static load: what the roof carries while parked

Once you're parked, the physics change completely. There are no cornering or impact forces, the vehicle's suspension and tyres absorb and spread the weight, and the telescopic ladder transfers a substantial share of the occupants' weight directly to the ground. That's why static capacity is typically several times higher than the dynamic rating - and why rack manufacturers publish separate static figures for exactly this use. Sleeping two adults in a rooftop tent is well within the static capability of a properly mounted, load-rated rack system.

The rules of thumb

• Driving: tent + rack weight must be under the vehicle's dynamic roof rating and the rack's dynamic rating.
• Camping: check the rack's static rating covers tent + occupants; the ladder does a lot of the work.
• Utes: tub racks and canopies usually carry higher dynamic ratings than the cab roof - one reason we recommend tub mounting for dual cabs. See our Hilux, Ranger & Amarok guide.
• Racks: the rack itself must be load-rated - more on choosing one in 2-Bar vs Platform Racks.

Still unsure about your vehicle? Your nearest dealer can check your exact setup and let you climb inside a Roof Space 2 before you buy.