What gives a pickup truck better mileage? Driving with the tailgate down or the tailgate up? Most people believe driving a pickup truck with the tailgate closed (or up) creates a wall the air hits and increases drag. Aerodynamic drag makes your truck (or any vehicle) get less mileage per gallon of gas. Others believe driving a pickup truck with the tailgate down lets the air flow more efficiently therefore lessening the drag. Less drag means better gas mileage.
This question (Tailgate down or tailgate up) has been something people have created their own ideas about based on how air flows. Common sense would make you think that driving with the tailgate down would be the best way to get the best mileage and save on gas. Assuming this will make some fuel conscious pickup truck drivers always drive with the tailgate down thinking they are getting better gas consumption.
The correct answer to this much debated issue is: Driving with your pickup truck with the tailgate up is more fuel efficient that with the tailgate down.
How can leaving the tailgate up be more fuel efficient?
When the tailgate on your pickup truck is closed or “up”, it actually increases fuel efficiency. This is because there is a type of air pocket created that is called a “separated bubble effect” within the bed of the truck. Wind that is flowing over your moving pickup truck bed is deflected by the bubble of slow moving air. This bubble of air pushes and guides the air over your tailgate making it more aerodynamically efficient. The effect of the vortex creates less drag which increases fuel efficiency.
Tailgate Up or Down – Explained
Is it better for gas mileage to leave your tailgate up or down when driving?
This video explained the fluid dynamics, and gives you the answer!
If this does not make sense to you, here is what happens when you drive with the tailgate open…
By driving your truck with the tailgate open, it kills the “separated bubble effect” and pulls the air toward the inside of the truck bed. This pulling action creates more drag instead of deflecting the wind. Therefore this reduces your gas mileage. This means it will cost more to drive your pickup truck with the tailgate down.
The Mythbusters BUSTED the pickup truck up or down myth by using 2 exact pickup trucks with one tailgate down and one up. The Pickup truck with the tailgate up went an extra 30 miles.
Do you have another theory on tailgate up or down? Please leave a comment below.