Jan 19, 2021
 in 
Autos

Myth Busted? Driving With The Tailgate Down Increases Gas Mileage

 By 
The Pit Boss

To drive with the tailgate down or up: that is the question.

You’ve probably heard this one before. Anyone you ask will have their own opinion, but I don’t stand by opinions alone. I’m concerned with the science behind whether or not driving with the tailgate down makes a difference in gas mileage.

Old-timers will swear up and down that driving with the tailgate down not only helps save on gas but that it helps the weight displacement to ensure smooth riding wherever you go.

Others will say it doesn’t make a lick of difference if the tailgate is down. There’s only one way to settle this. If you’re in the market for a truck, this article is of great importance. Can you drive with your tailgate down? Of course, just as long as the bed is empty. But is it worth it? Let’s discuss.

True or false: driving with the tailgate down saves gas.

Most people believe that driving with the tailgate down is a sure-fire way of saving gas. A common argument against the tailgate being closed (up) is it creates an invisible wall where the air hits, thus increasing drag. If you’re unfamiliar with how drag works, it can make your truck, or any vehicle really, produce less gas mileage per gallon. Whether you’re a lead-foot or enjoy cruising at a comfortable speed, drag makes its presence known either way. For those who swear by driving with the tailgate down for better gas mileage, the common reason is that the air flows more efficiently thereby easing the amount of drag on a vehicle. While it may seem plausible in theory, you’d be surprised by the results.  

Drumroll please...the answer for how to save money on gas in a pickup truck is by leaving the tailgate closed (up). That’s right; all those people who promised you driving with the tailgate down would save you dollars at the pump were misinformed. Still don’t believe me? How about some science to back it up?

Video source: Autoblog YouTube

When the tailgate is closed, it creates a specific type of airflow known as a separated bubble within the confines of the truck bed. While the truck is in motion, the bubble of slow-moving air deflects the wind over the raised tailgate. The surrounding air is guided over and across the bed of the truck resulting in a vortex effect. It’s this vortex effect that prevents any added drag.

Driving with the tailgate open is disastrous for the bubble effect, essentially negating any positive wind effect. The air is pulled toward the truck bed resulting in more drag instead of deflecting the wind.

So, there you have it. The commonly held myth about keeping the tailgate open has been destroyed. Aren’t you glad you looked up how to save gas while driving a pickup truck? Remember to keep that tailgate up so you can get the maximum amount of MPGs out of your pickup.

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