DISCLAIMER: Never exceed manufacturer's specifications. Doing so could cause property damage, injury, or death.
Understanding how much weight your car roof can carry is an important part of ensuring a safe, enjoyable, and smooth road trip experience. Whether you are looking to install a roof top tent for your next overlanding adventure, a roof box for some extra cargo space, or just have some gear you’d like to load on top of your vehicle, it is important to understand roof weight loading capacities.
Every vehicle is different- and so are their roof weight capacities. Determining how much weight your car roof can support is a key component and if not done correctly can be potentially hazardous to both you and other motorists on the road.
That’s why in this article, we’ll be covering everything that you need to know concerning how much weight a car roof can support and more. Personally, I’ve found this to be a very confusing topic with many motorists not quite understanding these concepts. My goal is to help you clearly understand your vehicle roof weight limits by the end of this article.
In short- there are 2 main roof weight limits which a car has to adhere to, namely static and dynamic weight ratings. As long as you do not exceed these weight limits you should be in the clear. Most vehicles have a roof weight limit between 70Ibs-165Ibs. This rating can be found in your vehicle owner's manual.
Why Roof Weight Loading Capacities Matter.
The main reasoning behind roof weight capacities is the performance of your vehicle. When you have additional gear or cargo on top of your vehicle roof, driving dynamics will be affected. This includes an increase in the difficulty of accelerating and braking.
On winding roads, additional risks can arise since the center of gravity of your vehicle will be affected as well as air streams around the vehicle body. Worst case scenario, the increased center of gravity can lead to the overturning of your vehicle due to overloading.
To avoid any potential hazards while driving on the road with additional cargo on your car roof it is mandatory to stay within the weight limits of your vehicle. You should also always aim to keep roof cargo as light as possible and not to load unnecessary items on your car roof, even if it is within the recommended weight limits for your vehicle.
Understand Your Car’s Static And Dynamic Roof Weight Ratings.
Next, we will cover the two main roof weight capacities you should be paying attention to when loading gear on your car roof- whether it be a roof top tent, roof box, kayak, or other gear. These 2 main roof weight limits include the- dynamic- and static roof weight capacity.
Car Roof Dynamic Weight Capacity.
Perhaps the most confusing part of the roof weight load limit is the dynamic weight capacity. The dynamic weight capacity of the roof refers to the amount of weight you can support on your vehicle roof while it is in motion. In other words, while you are driving.
The dynamic roof weight limit is always lower than the static weight capacity as this is what will be affecting your driving dynamics while you are on the road.
Most vehicles have a dynamic roof capacity of 165Ibs which equates to 74.8kgs. That said, this rating can be lower as well as higher, although the latter is much rarer. Your vehicle specifications should always be checked to determine your dynamic weight rating.
Car Roof Static Weight Capacity.
Static roof weight capacity is much simpler and something most people shouldn’t have to worry about too much. If you are, however, planning on mounting a roof top tent or other heavy gear on your vehicle you should pay a bit more attention here.
The static weight capacity refers to the amount of weight your vehicle can support on its roof when it is not in motion. In other words, when the vehicle is parked. The static weight capacity is generally much higher than the dynamic weight capacity. A general guideline is that static weight capacity is roughly 8x-10x greater than the dynamic weight capacity.
Where To Find Your Vehicle’s Roof Weight Limit Rating?
Now that you understand the difference between the static and dynamic weight capacity of your car roof, you are probably wondering- well how much weight can my vehicle roof actually support? The short answer is that it depends on your vehicle type, model, and year as well as if you have a roof rack or roof crossbars installed.
Making sure that you stay within the dynamic weight limits for your vehicle is the most important part to avoid any issues on the road. Static weight is also important, but as mentioned, this is only something you have to pay close attention to if you are planning on loading items such as a roof top tent which will receive additional weight once your campsite has been reached. (Since you will be getting in the tent).
The dynamic roof weight limits for your vehicle can be found in the owner’s manual. And it is important that you make 100% sure of your vehicle weight limits. Most manuals won’t specify any exact static load, we recommend sticking to the guideline of 8-10x dynamic load, or if you have a roof rack/crossbars installed stay within the load rating of those.
Roof racks and roof crossbars have their own dynamic and static load limits which will also have to be taken into account if you have these installed. These, however, won’t replace your car roof load limit, let me explain below-
Your Car Roof Capacity Is Only As Strong As Its Weakest Link.
If you are planning on mounting items such as a roof top tent or roof box to your car roof then it is absolutely necessary for you to install a roof rack or crossbars. Other items such as bikes, kayaks, etc. will also require you to have a roof rack or crossbars installed in order to make sure everything is securely attached.
In most cases, roof racks and crossbars are much stronger than the actual car roof itself and will have both a higher dynamic and static load rating. This, however, doesn’t mean that you will be able to add more weight onto your car roof- in fact, quite the opposite.
When you have a roof rack or crossbars installed, the weight of it will have to be taken into account as well. Thus, leaving less room for other items to be added to the roof.
That said, you should keep in mind that a roof rack or crossbars are necessary for loading other items as they provide critical mounting points and also help to distribute weight evenly across your car roof.
So even if your roof rack has a dynamic weight rating of 300Ibs, but your car only has a dynamic roof weight rating of 150Ibs, then it means you’ll only be able to load a total of 150Ibs on your car roof.
This includes the weight of the roof rack/crossbars which are generally 15-30Ibs leaving you 120-135Ibs to load other items if you had a dynamic weight limit of 150Ibs for example.
On the contrary, if your crossbars had a lower dynamic (or static) weight limit than your car roof then that would be the limit of how much you would be able to load, although this is highly unlikely.
For example– say your crossbars were rated at 130Ibs dynamic weight and your car roof rated at 150Ibs dynamic weight. Then it would mean you are only able to load 130Ibs on your crossbars, given that your crossbars are between 10-15Ibs in weight themselves.
Here are the 3 main formulas you should take into account when loading your vehicle-
Formula 1- For the roof rack/ crossbars.
- Load on the roof rack/ crossbars (roof top tent/ roof box/ etc.) < maximum load of the roof rack/cross bars.
Formula 2- For the car roof load.
- Load on the roof rack/crossbars + weight of the roof rack/ crossbars < permissible roof load.
Formula 3- For the total vehicle weight.
- Unladen vehicle weight + additional roof weight + luggage + passengers < total permissible vehicle weight. (Also found in the owner's manual).
Understanding Roof Aerodynamics.
While it is important to stay within the roof weight limits for your vehicle you should also consider the aerodynamics of the items you are loading onto your car roof. For example- roof boxes and roof top tents are designed to be as aerodynamic as possible to avoid influencing your car’s maneuverability.
If you are loading less conventional items onto your car roof such as a sofa for example (not recommended), then aerodynamics will be different and in many cases off-centered. This will influence your vehicle’s maneuverability and steering whereas aerodynamic items such as a roof box won’t have as much of an effect.
It is important to take things like this into account to avoid creating hazardous situations on the road.
Factors That Affect Car Roof Weight Capacities.
Although vehicle manufacturers give set roof weight limits there are some cases where other factors will apply, unfortunately lowering your roof weight limit even further.
Off-Roading.
When testing roof weight limits and setting guidelines most manufacturers are only using urban roads meaning tarred roads as found in modern cities. These roads are far smoother than rural or off-road roads. Some manufacturers will also specify an off-road dynamic rating.
(Keep in mind, light off-roading shouldn’t be a problem, it is only when you are in heavy off-road conditions, such as where the vehicle is swaying from side to side that you should take the following into account).
When going off-roading with a load on your car roof it is recommended to stay well under the recommended dynamic rating. We recommend staying 10-20% under the dynamic weight rating.
That would mean if your vehicle had a dynamic weight capacity of 165Ibs that you should be aiming to have no more than 132-148.5Ibs on your car roof.
Sunroof.
If your vehicle has a sunroof installed, you’ll have a far lower roof weight capacity than other vehicles of the same make which don’t have a sunroof installed. We don’t have any specific guidelines if you have a sunroof installed. It is recommended to check your owner’s manual or to contact your vehicle manufacturer to find this rating.
Below is a video explaining a lot of what we've covered so far, I highly recommend watching it to ensure you understand all the concepts-
Why Do Roof Top Tent Manufacturers Exceed Permissible Roof Load?
You may be wondering why roof top tents are so heavy if there is only so much weight that can be carried on a car roof while in motion? Well, the main problem is the materials. Roof top tents must be designed to be durable, strong, and protective.
Conventional roof top tent materials provide great durability, insulation, and protection ensuring that you can use your tent in almost all weather conditions. These materials are, however, also quite heavy.
That said, manufacturers such as iKamper and Roofnest provide some great lightweight tent options as well which still provide great durability and protection.
Can My Car Support A Roof Top Tent?
In short- as long as your roof rack and roof top tent are under the dynamic weight limit of your vehicle your car should be able to support a roof top tent. Generally, bigger vehicles such as pickup trucks and SUVs are recommended, but you should be able to get away with something smaller as well.
Roof Loading Do’s And Don’ts.
Do's
- Stay within your roof weight limits.
- Avoid carrying unnecessary gear on your rack or crossbars.
- Use proper cam straps to secure your load.
- Carry bulky gear that can’t fit in your vehicle.
- Carry dirty gear such as firewood for example.
- Use the locks on your rack accessories as they serve as a backup to the securing mechanism.
- Carry only aerodynamic gear on your roof rack/ crossbars.
Don'ts
- Go over the roof weight/ roof rack limits.
- Use bungee cords or twine to secure your gear.
- Load unnecessary gear on your roof.
- Leave gear or rack accessories on your vehicle when not in use. This can cause additional wear and tear on your vehicle systems and tires. As well as increase gas mileage.
Conclusion.
Utilizing the extra space on your car roof for accessories like roof top tents and roof boxes is a great idea and can make your road trips and overlanding experiences far more enjoyable and memorable.
That said, it is important to stay within the roof weight limits of your car and not to push your boundaries. Always make sure that gear and accessories are properly secured. Also, try to keep your vehicle’s center of gravity as low as possible by removing unnecessary items from your roof rack or crossbar system.
For example- If you are going overlanding with a roof top tent, instead of carrying jerry cans on the roof rack system, install a mounting system at the back of your vehicle to store them. This way you will lower the center of mass of your vehicle while only keeping necessary items on the roof rack such as your roof top tent in this case.
