Can Driving With A Truck's Tailgate Down Really Help Your Fuel Economy?

Gas prices remain stubbornly high and are likely to stay that way for the immediate future, which leaves car owners facing the task of trying to offset the increased costs. Naturally, that has led many drivers to look for ways to cut their fuel consumption, and there are no shortage of tips and tricks floating around online that claim to do exactly that. Some of these can actually be useful, while others will make no difference to a vehicle's fuel economy or might even make it worse.

Driving with a truck's tailgate down is one of the tips you might have seen offered up as a way to save fuel, but tests have repeatedly proved that it's not a good idea. Speaking to Autoblog back in 2014, Ford's then-exterior design manager for the F-150, Brad Richards, said that wind tunnel testing showed that the truck's drag increased by 8 percent with its tailgate down. Increased drag leads to poorer fuel economy, which is the same reason why it's always best to remove accessories like bike racks from vehicles when you're not using them.

A year prior to Ford's test, Consumer Reports conducted a similar comparison with a Dodge Ram 1500. At highway speeds, it found that leaving the tailgate down decreased the truck's fuel economy by around 4 percent. Long before that, a research paper spearheaded by the National Research Council of Canada echoed Ford's findings, reporting that dropping the tailgate increased drag and therefore had a small negative effect on a truck's economy.

There's plenty of evidence, then, to show that driving with the tailgate down isn't going to boost a truck's mpg. Instead, it's more likely to have a negative effect to some degree. Though, exactly how much of a negative effect it has will vary between different makes and models of truck. When Mythbusters put the idea to the test by driving two identical mid-'00s Ford F-150s until they ran out of fuel, the truck with its tailgate up travelled almost 30 miles further on a full tank.

Dropping the tailgate is one of the many ways you can end up accidentally wasting fuel, but there are still plenty of other tips that can actually make a positive difference to your truck's fuel consumption. According to the EPA, accelerating and braking more gradually can make a particularly big difference, especially in stop-and-go traffic. Removing unnecessary weight can also cut fuel usage to a smaller degree.

Increased speeds can also reduce fuel economy significantly, to the point where the EPA says every additional 5 mph over 50 mph is the equivalent of paying $0.29 extra per gallon for gas (assuming an average price per gallon of $4.10). Keeping your truck's tires correctly inflated can also help save money at the gas pump, with Michelin claiming that underinflating tires by 14 PSI can dent efficiency by as much as a full tank of fuel each year.