Aerodynamics on pickup trucks are weird. With testing showing that tailgate UP gets better economy than down, it kind of throws conventional wisdom out the door.
As Harry says, even if it does, you'd almost certainly never notice the difference. This assuming the canopy is flush with the roofline of the truck, and not sticking up above. If it sticks up more, the drag would be increased significantly.
Not noticeably. The engine is the culprit here, as well as slow rear gears and no overdrive.
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so they say, but youd never notice
