When you start thinking about roof top tents, one of the first questions that arises is whether or not the roof of your car can support it.
For most roof top tents, there's a straight forward roof rack combination that will work for your vehicle. For some heavier tents - usually those that fit 3+ people made with an aluminum rather than fibreglass - there are specific roof rack solutions to consider.
There's a few factors to consider between your car, the roof rack and roof top tent.
Max Roof / Rack Load
Believe it or not, there is no universal standard as to how much weight you can put on a car. You can usually find a number buried within the car specifications or directly on your roof rack, and if you search the internet usually end up finding something saying around 150 to 170 lbs.
That being said, it's always best to confirm the number or get a second opinion. For each car, it ultimately depends on where the structural supports are (within the car frame) and ensuring that the roof racks are also rated to support / distribute the weight properly.
You might also be thinking that a few folks sleeping in a tent is way more than 170 lbs, and you'd be right! That's because there are actually two types of weight loads to be considered.
Static vs. Dynamic Weight
Static weight is usually not the issue when talking about loading things onto your roof. As long as it's supported properly, where the weight is transferred through the car frame, it's no different than a car built to carry its occupants.
Dynamic weight capacity (DWC) is the maximum weight that can be carried when the vehicle is in motion. The DWC accounts for the stress the additional weight causes when your car is in motion. For example, when you break suddenly and all the weight of your car is transferred to the front.
When installing a roof top tent, a few important things to keep in mind:
- Check that BOTH the roof of your vehicle and the roof rack have dynamic weight capacities that can support your tent
- The maximum capacity of your roof-rack system will be dependent on the LOWEST-RATED part of the system
- Don't forget to subtract the weight of the rack itself from the DWC limit!
Two things to ensure the weight of a roof top tent is distributed properly include ensuring that your cross-bars that can handle the load and spacing them apart properly.
If the improper cross-bars are used, they may bend or strain under the weight - which reduces their ability to properly spread the weight. Similarly, spaced improperly places greater strain on certain areas of your roof rack - which they might not be designed to handle. Specific mounting points for the crossbars are typically based on where the strongest points of the roof are located. If installed at different distances apart, your rack would have an unknown weight capacity which could damage the rack or the vehicle roof.
Always refer to the manufacturer instructions of the roof rack to ensure they're properly installed. Similarly, it's worth checking the roof top tent requirements too. For example, iKamper provides a detailed page on their Mounting Requirements.
Handling / Centre of Gravity
A question that occasionally comes up is if a roof-top tent increases the risk of roll over.
While your vehicle will have a slightly higher centre of gravity, there are two things to remember:
- The weight is flat and well distributed across your whole roof top. This is also why vehicle roofs and racks have spacing and weight limits.
- A Roof Top Tent that weighs 160 lbs is a fraction of your 4,000 lbs+ vehicle.
At the end of the day, it is of course completely up to you to determine what you are comfortable with on your rooftop. It is critical that you do your own research ahead of a purchase to ensure that your vehicle can support the weight.
Drive safe and keep your tires on the trail!