The roof rack is like the Swiss army knife of overland accessories. A well-fitted roof rack can provide storage, lighting, shade, a place to sleep, and security for your equipment, tools, and outdoor gear. It can free up space inside your rig, keep dirty or smelly items out of the truck, and even offer a convenient place to stand up high to get a better view of wildlife or the road ahead (only while the vehicle is stopped, of course).
A solidly built roof rack system will last the life of your vehicle. It should blend seamlessly with your rig’s bodywork, and mount securely enough that you’ll never have to give it a second thought. It should become an extension of your overland vehicle itself, rather than a separate accessory.
But how do we decide which rack will fit best on our rigs? How do we know if it will handle the loads we throw at it? What are the best ways to accessorize our racks to get the most utility out of these versatile tools? How do we make sure our vehicles stay safe both on the trails and on the tarmac with a load up top? As Clay says in the video below, the guiding rule for roof racks should be “As little as possible but as much as necessary”. Let’s look at why this is.
Factory roof racks that are installed as standard equipment on many 4x4’s come with a manufacturer’s load rating. In nearly all cases, this falls between 100 and 150 pounds. That’s not a lot. Most roof top tents alone weigh between 150 and 200 pounds, never mind the awnings, jerry can holders, boxes, firewood, and other accessories you may want to mount on your roof.
Why the low number? While most stock roof racks can likely handle more than 150 pounds of weight, the manufacturer’s main concern is vehicle stability. Adding weight to the top of the car raises the center of gravity, which can dramatically change the way it handles both on road and off.
If you’ve driven a truck with a tall camper on it or an SUV with a heavily loaded roof rack you’ll be familiar with that “tippy” feeling you get as you drive around corners. In the case of an emergency maneuver, that extra weight upsets the vehicle’s balance, and in extreme cases can even contribute to a rollover.
This is why it’s important when you’re adding an aftermarket roof rack to consider carefully both what you’re going to load on the roof, and how you might modify the rest of your vehicle to compensate for that extra weight. To make these calculations, there are two kinds of load ratings to think about: static load limit and dynamic load limit.
Very simply, the static load is the total weight of all the items you intend to load onto your roof rack while the vehicle isstationary. Dynamic load takes into account the physical forces that total weight imparts on the vehicle while it’sin motion. For any roof rack dynamic load ratings are always going to be lower than static load ratings.
For example, let’s say the roof rack you’re considering, such as the Eezi-Awn K9, has a static load rating of up to 1000 pounds. That rack’s dynamic rating, however, is 500 pounds. Why take into account both numbers? If you can’t drive the car with 1000 pounds of gear on top, why bother thinking about the static load?
The best illustration of this is the roof top tent. While in motion, the empty tent might only contribute 150 pounds of weight to the total, but when you get ready to tuck into bed for the night, you might be adding 300-400 pounds of extra weight to the rack while your rig is parked in camp.
The higher the dynamic load limit your roof rack is rated for, the more wiggle room you’ll have for static loads.
Something we’ve covered briefly before in our article on storage solutions is the loading of roof racks. Because of the changes in the center of gravity that heavy items impart on a vehicle that’s already likely pretty tall, the lighter and lower profile the load you can manage, the better. Planning ahead of time what you might want to load up top will help guide your buying decision.
Feather-weight and weather-tight aluminum storage boxes, like those from Alubox and Zarges, are a great accessory for storing lighter items like clothing and some kinds of tools and spare parts up high. Awnings can weigh thirty or forty pounds, but mobile shade solutions are nearly a must if you plan to travel a lot in remote places. Lengthy and often grimy tools like shovels, axes, and traction boards are also great candidates for roof rack storage.
You almost never want to carry extra fuelinside your vehicle (both for smell and safety), but liquids are heavy, and hauling five gallon jerry cans up and down off the roof demands a strong back. The same goes for spare wheels and heavy recovery tools like Hi-Lift jacks. If your vehicle can accommodate a bumper-mounted solution for these kinds of weighty items, you may be better off.
Roof racks can also affect vehicle aerodynamics and therefore fuel economy. My old school Land Rover Defender is not exactly a wind tunnel champion, but I was surprised to gain 3-4 mpgs in highway driving with my - admittedly very tall - roof rack removed. So, keeping your loads as close to the roofline as possible will be a loading strategy that can benefit any vehicle.
With these weight and loading variables in mind, what’s the best way to go about choosing a rack for your vehicle? Gone are the days of totally generic roof rack applications - all the best manufacturers make racks that are designedspecifically for most modern off road vehicles.
The popular “flat rack” option, like those offered by ARB, Eezi-Awn, and Prinsu, create a strong, solid base that bolts directly to your rig’s existing mounting points. Their low-profile hugs the roofline for better aerodynamics. Flat racks’ modular construction also makes for easy installation and adjustments, and opens up a wide universe of accessories and load-lashing options.
Don’t need a full-length rack for your rig? You can look to more traditional cross bars like Rhino-Rack’s Backbone or Vortex models, also designed with your specific rig in mind. These are especially good for loading up outdoor equipment that make your adventures that much more fun, like kayaks, fly rods, and bikes.
Questions about racks? Want to talk about accessories? Hit us up in the comments below, or call one of our experts to hash out the roof rack details for your rig.
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