Ratcheting straps are much less likely to fail when moving a bulky item like a mattress.
How to tie a mattress to roof racks.
Drive on surface streets if possible to avoid heavy air pushing up on the mattress at the front of the car.
Once tightly packed in the mattress bag haul the mattress onto your roof and center it in the middle.
Pull the rope tight so there is no extra slack.
Be sure to crisscross the rope over and under the mattress and roof to secure the mattress to the car.
If you do put it on the roof of your vehicle have a strap run from front to back as well as from side to side.
Tie the rope that you placed the mattress on in place.
After the mattress is secure in the plastic place the mattress on the roof.
This will stress any knot no matter how securely tied.
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.
If you do secure your mattress to a roof rack or safely in the bed of a truck strap it down with ratcheting straps.
Center the mattress in the middle and put the rope over the length of the mattress.
Then place the rope across the mattress length wise then secure both ends starting with the front then the back to the front and back bumpers respectively.
Use a tie down that wraps around the item and the rails.
Roll down all windows.
Secure the front end of the mattress and then the other end of the mattress.
I came across a guy on the highway that only had a strap going across.
On each side of the roof you ll see a rack that runs the length of the roof of the vehicle.
The mattress had lifted up in the front and ripped the roof racks right off.
Put the mattress on top of the car and rope so that it goes length wise with the length of the car see pics above.
Put a piece of rope on the roof of the car that goes from back bumper to front bumper.
Mattresses are large bulky and can pick up resistance from the wind.
What types of tie downs work best.