Learn how to calculate your vehicle’s true roof load capacity to safely carry rooftop tents and gear without compromising stability or insurance on your next trip.

Overview – Why This Matters

This guide is for 4WD tourers and families who carry gear on their roof, specifically those using rooftop tents or boats. It solves the critical confusion between “dynamic” and “static” weight limits and explains how off-road driving significantly reduces your legal carrying capacity. You will learn how to verify your specific vehicle’s rating and pack safely for your next adventure.

Words and Photos The Adventuring Pals

Another Important Measure to Learn?

Many experienced caravanners would be familiar with weight limits that apply to towing capacity, GCM, GVM and even Axle limits. I know, it was a steep learning curve for me to learn all these terms when I first purchased a caravan.

But did you know, there is also a weight limit on what you can load up on your roof? This is important to know when you start trying to load up a roof top boat or, like us, a rooftop tent as well as tow your van.

The maximum amount of weight you can apply to the roof, including the roof rack system itself is specified by the vehicle manufacturer.

Finding Your Vehicle Roof Load Rating

You can find this out by checking your owner’s manual, contacting the vehicle manufacturer or checking Redbook.com.au for the specs. Just be sure to choose your exact model specs.

Most 4WDs can do up to 100kg while travelling, with some at 150kg and rarely higher. One example is the 200 Series Landcruiser, with a roof load rating of 200kg, but only when using a specific roof rack system.

Along with the vehicle manufacturer’s roof loading limit, you will also have to abide by any limits that the roof rack system manufacturer may have, and you will have to follow the lower limit.

Calculating Off-Road Load Reductions

Quite often these are reduced further, the more you go off road. Sometimes by as much as 75%! Off road is defined by anywhere that is not a sealed road, including gravel roads.

Understanding Dynamic Versus Static Load Ratings

This really matters when you talk rooftop tents, as you can imagine, a family of four like us, would quite easily exceed the roof limits of even the highest amount, especially when the roof-top tent and racks weigh in at 80+ kilograms.

But fear not. The stated limits are what is called the Dynamic Weight Limit. This means it is the rating of the load when the vehicle is in motion and the load is bouncing up and down.

When the vehicle is stationary and the load is not moving, it is now a static load.

Now admittedly, it is a lot harder to find out the Static Weight Capacity. But the static limit can endure a bit more than the dynamic limit due to the absence of forces applied when stationary as opposed to when in motion.

How Roof Loads Affect Vehicle Performance and Economy

All this extra weight up high on the vehicle is going to drastically affect its performance both on road and off-road.

It will also affect the fuel economy and likely increase in-cabin road noise from the wind’s effect on the load up top.

When travelling, we try to minimise the weight up top and only have the bare essentials.

In our case we have the rooftop tent, a 270-degree free standing awning and a set of MaxTrax for easy access when needed.

Distinguishing Ute Cab versus Canopy Load Limits

Having a ute setup with a separate canopy, we actually have two different load limits: one for the car roof and another for the canopy roof.

Your roof limits will dictate what roof top tent or tinny you can safely carry.

So as you can see, it is an important thing to think about. There’s a bit more to loading up the roof then just chucking it up there and hoping for the best.

Highlights

✅ Check the Manual: Verify the manufacturer’s limit in your owner’s manual or on Redbook.

✅ Calculate Rack Weight: The limit includes the weight of the rack itself, not just the cargo.

✅ Off-Road Reductions: Remember that off-road travel (unsealed roads) can reduce capacity by up to 75%.

✅ Dynamic vs Static: Ensure your driving weight meets the Dynamic limit; your parked weight (sleeping in a tent) relies on the Static limit.

Glossary

• Dynamic Weight Limit: The maximum weight rating of a load when the vehicle is in motion and subjected to forces like bouncing.
• Static Weight Limit: The weight capacity when the vehicle is stationary and the load is not moving. This is typically higher than the dynamic limit.
• Off-Road: Defined in this context as anywhere that is not a sealed road, including gravel roads.
• GCM: Gross Combination Mass. The most your Caravan and Tow Vehicle can weigh, other weight limits permitting
• GVM: Gross Vehicle Mass. The most your Towing Vehicle can weigh, other weights limits permitting

FAQs

Q: What is the difference between dynamic and static roof load?
A: Dynamic load is the weight limit when the vehicle is moving, while static load applies when the vehicle is stationary, such as when sleeping in a rooftop tent.

Q: Does driving off-road change my roof load limit?
A: Yes, many manufacturers reduce the roof load limit for off-road driving (unsealed roads), sometimes by as much as 75%.

Q: Does the roof rack count towards the weight limit?
A: Yes, the maximum weight includes the roof rack system itself, not just the cargo you put on top.