Say you go out this holiday season and get a Christmas tree that’s some Griswold-level shit. Or you have an old-school, 17-foot aluminum canoe. Or you like to surf. Or you’re driving your nasty old mattress to the dump after you failed to unload it on some Craigslist chumps. No matter how big your car is, you won’t fit any of that stuff inside. No, you’ll want to strap those things to your roof.
But when strapping gear to your roof, make sure you do it right. A US government study found that in 2010, around 51,000 crashes, 10,000 injuries and 440 deaths were caused by objects falling from another vehicle, and you don’t want to contribute to statistics like that. Which is why we spoke with Jonny Wood — one of Yakima’s four “Road Warriors” who travel around the US educating the masses on how to properly rack up their vehicles — and asked for some advice on how to properly secure a load to a car’s roof.
Acquire ropes and straps. Wood recommends a webbing strap with a fastening buckle that doesn’t use a ratcheting system. According to Wood, ratcheting systems “apply a significant amount of crushing force on whatever you’re moving, so you can go in excess of what’s necessary on both whatever you’re carrying as well as the vehicle.” If you do go for ratchets, just be wary of how much you tighten. Wood also advises against bungie cords, as they’re too prone to flex when driving at speed and causing loads to shift and possibly escape. Nylon rope also works, but be prepared to tie some trucker’s knots.
Assess your rack situation. “There are really three kinds of scenarios for your roof,” Wood said. “There’s the scenario where there’s absolutely nothing on the top of your roof. Then there’s the scenario where you have side rails and then a scenario where you have side rails and crossbars.” Wood says side rails and crossbars are ideal, but you can move whatever you you need to without them. In the case of a naked roof, you should be looping the rope through the car (through the doors, not the windows) and around the object on the roof, and a towel or blanket should be used to protect the roof of your car from the object. If you have side rails and crossbars, the straps can be looped around those.
Placement matters. Placement of the item is important to get right. In the case of a bare roof you’re somewhat limited, but in this situation it’s ideal to have the object centered with the doors of your car so the bulk of the item is most securely strapped down. If you have side rails, the most important thing is to reduce the amount of drag the item will make by placing the front of it in line with the beginning of the roof (or moving it as far back as you can). When the item hangs over the windshield, it causes updraft force on the car, “because more of that object is catching the wind and causing it to pull upwards away from the vehicle,” said Wood.
In the event of overhang, anchor fore and aft. If you’re attaching something particularly long, like a tree or a canoe, overhang is unavoidable. In this case, you’ll want to anchor the item not just to the rack but the front and back of the vehicle. “The real big no-no is to hook on to a plastic bumper,” said Wood. “Find a metal structure on the rear of the car. On the front of the car, it’s not as easy to find one, so you can get something called Hood Loops anchor loops. Open up your hood and you’ll find bolts on the sides you can attach these loops to…that creates an anchor point.”
Adjust your driving. Wood said most roof rack systems for cars have a dynamic roof load of about 165 pounds. This means that, assuming you’ve strapped everything down properly and your load doesn’t exceed that weight, you should be in the clear to drive as you normally would at highways speeds. However, if you intend to carry more or you don’t have a roof rack, you should drive slower, as the added weight to your roof can negatively affect your car’s handling and aerodynamics.
Check the load. Naturally, you’ll want to do some stress testing before you set off by pushing and pulling on the object to make sure it’s snugly in place. But it shouldn’t stop there. “If you’re going on a long drive on the highway, plan your trip accordingly, where in the first five miles after you’ve been driving at speed, [stop and] double-check everything to makes sure its all good,” said Wood. “That’s one of the big things we recommend — checking after it’s been acclimated to real-world driving.”