Two equally spaced straps running front to back and two side to side across the load will do the trick for most standard shaped items.
How to secure a load on roof racks.
First place smaller items together in a tub or suitcase.
First loop the strap under the roof rack s crossbar and drape the loose ends over your oblong load i e.
Then secure the front and back ends of each lumber bundle with ratchet straps to prevent movement photo 1.
Wood said most roof rack systems for cars have a dynamic roof load of about 165 pounds.
Refer to rooftop tent and rack manufacturers for more details.
Then you can begin organizing the cargo on the roof of your car.
Use proper cam straps to secure your load.
Ratchet straps are a cheap and easy way to ensure the highest level of safety when deciding how to secure items on a roof rack.
Rope is ok but you have to master several fancy knots for it to be safe.
After packing the cargo on top of the car use your tie down materials to secure the load.
With the third option crossbars with side rails you can secure an item to the side rails and run tie downs from front to back securing them to the crossbars.
Next secure the load to the rack using ratchet straps photo 2.
Carry bulky gear that won t fit in your vehicle.
The second option is the side racks.
Next pull the long end of the strap under the crossbar on the.
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.
Carry dirty gear like.
That prevents the bundle from sliding forward backward or side to side.
Place heavier items on top of lighter items to keep them in place and all items should stay centered between the doors.
Start by loading dimensional lumber onto the rack with the narrow edges resting on the crossbars.