You’re a couple of searches and a simple calculation away from figuring out if your car can handle a roof top tent safely and without risking any damage during actual usage. In most cases, if you own an SUV, Jeep, van or truck, you’re good to go, whilst sedans, hatchbacks, coupes are almost never a safe fit for a roof top tent. On top of that, you can pretty much rule out putting a roof top tent on any vehicle with a rooftop load limit under 165 lbs.
But let’s jump to the steps you should take to be absolutely sure you can buy, install and safely drive with a roof top tent.
Step #1: Finding Out Your Car’s Manufacturer Recommended Rooftop Load
Finding out your car’s maximum roof top load is usually done by checking your owner’s manual and / or the manufacturer’s website. If you’re using your manufacturer’s website, make sure you select the correct make-model and year to get reliable number. Worst case scenario, you won’t easily find this information listed, but there are always popular forums to point you in the right direction – just don’t 100% trust any random guy that tells you a rough number.
Consideration #1: your roof is way more sturdier than you think and it’s actually a safety feature, in case your vehicle rolls over. You’ve probably seen that cars that roll over don’t have their roofs and passenger area crumpled and that’s because their roll cages are made to support a lot of weight to protect its inhabitants in case of accidents. Or carry massive roof top tents.
Consideration #2: keep in mind that there’s a discussion to be had about static load vs. dynamic load, so you might be looking at two numbers in reality:
(1) Your car’s maximum roof top static load
(2) Your car’s maximum roof top dynamic load
Step #2: Figuring Out Static & Dynamic Load
Simply put, the static roof top weight limit refers to how much weight you can put on your car’s roof (ex.: actually using a roof top tent and sleeping in it with a 2-3 other people) and the dynamic roof top weight refers to how much weight you can put on your car’s roof (ex.: actually driving with a roof top tent installed and closed / folded). We’re going to make a safe assumption you won’t be driving while people are sleeping in the roof top tent…
Also keep in mind that the static load is always higher (much higher to be more-or-less precise) than the dynamic load.
Step #3: Checking Your (Future) Roof Top Tent’s Technical Specifications
Whenever you’re buying a roof top tent, make sure to check its technical specification and save two numbers:
(1) Total Roof Top Tent Weight – very important!*
(2) Roof Top Tent Weight Limit / Load Limit** – this should tell you how much weight it can safely support.
* Why is it important? It’s very important because the roof top tent’s total weight (when closed / folded) is considered a dynamic load when you’re driving and most maximum roof top loads actually mean dynamic loads, not maximum loads supported when stationed.
** Ok, why? Well, consider this – a roof top tent might be marketed as a 4 person roof top tent, but they might be using Vogue models…so you should always question marketing and actual add up the total weight of accessories you’re going to put in that RTT and the weight of all the people that will be sleeping or spending time simultaneously inside. You might be surprised that a 4 person roof top tent will actually fit 4 people, but isn’t designed or tested for their total weight in your specific scenario.
Step #4: Buying the Right Roof Racks for Your (Future) Tent
Most likely your choice of a roof top tent doesn’t come with a roof rack included in the kit and it’s, unfortunately, a critical piece of equipment you have to invest in.
Considering that the brands designing the roof top tents have gone through extensive testing and (at least theoretically) know their product inside-out, your best options of buying a roof rack are as follows:
(1) Best Bet: buy one of the roof racks they’ve tested and recommend.
(2) Next Best Bet: buy a premium, heavy duty roof rack. Considering the prices of roof top tents, this is one accessory you shouldn’t look at saving money when purchasing.
(3) Risky Move: buy popular roof racks that aren’t typically considered heavy-duty or are very close in terms of maximum weight load limit to the RTTs actual weight. It’s risky because you might be putting on more weight than you think (think of the guests!) and you’ll end up damaging your car, roof racks and roof top tent in a worst case scenario.
We’re going to refrain from recommending any roof racks in this scenario, as it’s always best to decide based on what roof top tent you’re looking at and what vehicle you’re installing it on.
Step #4: Estimating Maximum Total Payload
A couple other things to look at are GVWR, which stands for Gross Vehicle Weight Rating and CW, which stands for Curb Weight (total weight that your car weighs when sitting on the curb / not moving, without any passengers or heavy-weight accessories and aftermarket parts such as roof top tents).
These two numbers can be annoying to find at times (some vehicles have them listed on a placard on the driver’s side door for example) and your best and safest bet is to look them up in the owner’s manual and/or the actual manufacturer website. We wouldn’t recommend trusting figures thrown around on forums, as these numbers have some serious implications on your ability to safely drive your car.
Now that you have the information on GVWR and CW, there’s a simple calculation to be made:
GVWR (Gross Vehicle Weight Rating) – CW (Curb Weight) = Total Payload Capacity or Supported Payload
Knowing the supported payload, you should now get some peace of mind by making the following calculation:
Passengers’ Weight + Roof Top Tent & Accessories Weight < Supported Payload
It’s as simple as that and in 99% of the cases you’ll see that the total weight of passengers and the roof top tent plus any accessories is less than the supported payload.
Step #5: Get Some Peace of Mind
In most cases, it’s just nice to see what other overlanders are doing and if you search for “my make-model roof top tent”, you’re sure to find all sorts of RTT kits guaranteed to work for your vehicle and you might discover some cool builds with RTTs, giving you some extra piece of mind.
You Should Also Know That…
…weight limitations are the main concern of most roof top tent buyers, but there are a few other things you might want to consider, from gas mileage to wind resistance.