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TECHNICAL GUIDE · SAFE FITTING
Static load and dynamic load: what you need to know before fitting your roof top tent
Two figures decide whether your car and your bars can carry a roof top tent safely. We explain what they mean, how to calculate them and which mistakes to avoid.
Dynamic loadStatic loadReal examplesThule and Cruz
When someone asks us whether their car can carry a roof top tent, the answer hardly ever depends on whether the car is “big or small”, but on two numbers found in the vehicle and roof bar documentation: the dynamic load and the static load. Understanding them is the difference between a safe installation and a problem on the road. If you are still choosing a model, also read our complete guide to choosing the ideal roof top tent.
The key concepts
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Dynamic load
The maximum weight the roof can carry while the car is moving: braking, bends, bumps and wind. Only what is on the roof while you drive counts here: tent + bars.
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Static load
The weight the roof can carry when the car is parked. It is much higher than the dynamic load because there are no inertial forces. Here you add the tent, the bars, the people sleeping inside and their luggage.
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Roof bar capacity
Bars have their own limit too. It does not matter if the car can take 100 kg if your bars are only rated for 75 kg: the lowest limit always applies.
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Own weight
Do not forget to add the weight of the bars or platform (usually 5 to 25 kg) to the weight of the tent. It is the most common mistake when doing the maths.
How the weight is distributed
🚗💨 Tent + bars 🅿️ Tent + bars + People + Mattress and bedding
✅ The golden rule
Tent weight + bar weight ≤ the lowest dynamic load (the car roof’s or the bars’). If this is met and the car is parked on level ground, the structure is designed to carry the people sleeping inside: as a guide, the static load is around 3 times the dynamic load, but the figure that counts is always the one given by the manufacturer of your car and your bars.
Real examples
| Case | Dynamic load (car / bars) | Tent + bars | Driving | Parked (estimate) |
|---|---|---|---|---|
| Mid-size SUV with 100 kg bars and EVEREST 135 tent (69 kg) | 100 kg / 100 kg | 69 + 6 = 75 kg | ✅ 75 ≤ 100 | 69 + 6 + 2 adults (160) + bedding (15) = 250 kg · ✅ within ~300 kg |
| Compact car with a 75 kg roof and a FAMMAX V2 tent (51 kg) | 75 kg / 75 kg | 51 + 6 = 57 kg | ✅ 57 ≤ 75 | 57 + 2 adults (150) + bedding (10) = 217 kg · ⚠️ within ~225 kg, but very tight: confirm with the manufacturer |
| 4x4 or pick-up with a 150 kg platform and SAHARA 160 family tent (65 kg) | 150 kg / 150 kg | 65 + 25 = 90 kg | ✅ 90 ≤ 150 | 90 + 2 adults (160) + 2 children (60) + bedding (20) = 330 kg · ✅ within ~450 kg |
Tent weights as stated in their technical sheets on braguscamp.com. The “parked” values use the rough estimate of 3 times the dynamic load; always check the real figure in your vehicle and roof bar manuals.
Where to find these figures
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Vehicle manual
Look for “maximum roof load”. It is usually in the technical data or roof rack section.
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Bar manual and label
Quality bars state their maximum load, the tightening torque of the bolts and whether they are tested to ISO 11154.
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Roof type
Raised rails, flush rails, fixed points or a bare roof: each needs specific feet. Thule recommends using a tent on raised rails only with additional support.
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Panoramic roofs
If your roof is glass or panoramic, confirm with the car manufacturer that it can take a roof top tent before buying anything.
Why you should always choose a leading brand
For roof bars and racks, the reference brands in Europe are Thule and Cruz. It is not about the name: it is about what is behind it.
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Testing and standards
They design and test their bars to ISO 11154 for roof load carriers, with strength and crash tests.
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A specific kit for your car
They have fit guides by make, model and year, with feet and fitting kits designed for each roof.
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Clear figures
They state the maximum load, the tightening torque and the fitting instructions, so you can do the maths with real data.
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Warranty and spare parts
If a bolt or part is missing, there are official spare parts and technical support.
⚠️ Be careful with generic bars from Amazon, AliExpress and similar sites
Many unbranded bars sold on these platforms do not state any standard (neither ISO 11154 nor crash tests), do not publish a verifiable load rating, and the seller cannot confirm that they are safe for carrying a roof top tent, which is a heavy, tall load exposed to the wind. The most common problems are feet that slip, thin profiles that flex and bolts that work loose. Choosing a leading brand such as Thule or Cruz avoids most mistakes from the start.
Safe fitting checklist
- Check that tent + bars does not exceed the lowest dynamic load (car or bars).
- Use the feet and kit specific to your car model and respect the distance between bars given by the manufacturer.
- Tighten the bolts to the specified torque and check them again after the first 50–100 km.
- Fix the tent to the bars with its mounting system (on our tents, LockNLoad T-track) and check there is no play.
- Remember the car’s new total height for garages, car parks and tolls.
- Drive smoothly: the centre of gravity is higher and crosswinds are more noticeable.
- Park on level ground to sleep and do not exceed the static load with people, mattress and luggage.
We help you get it right
We manufacture roof top tents and know the limits of each model. Tell us the make, model and year of your car and which bars you have, and we will tell you which tent fits. And if you visit our Madrid warehouse by appointment, we will fit the roof top tent for you.
Frequently asked questions
Can I sleep inside even if my car’s dynamic load is 75 kg?
Yes, as long as you do not exceed the static load with the car parked. The dynamic load limits what you carry while driving (tent + bars); with the car stationary, the structure spreads the weight of the people over the roof, the pillars and the bars.
What happens if I exceed the dynamic load?
The roof, the mounting points or the bars can deform or break, the car handles worse in bends and under braking and, in an accident, your insurer may raise problems. It is not worth the risk.
Can I use the bars that came with my car?
It depends on their maximum load and mounting system. Check the manual. If they do not state a sufficient load, replace them with Thule or Cruz bars with the kit for your model.
How many bars do I need?
Usually two, spaced as the tent manufacturer indicates. For long tents or on pick-ups, a platform or three bars is sometimes recommended to spread the weight better.
Can your car carry a roof top tent?
Send us the make, model and year of your car and we will help you choose the right tent and bars.
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