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How Much Does A Tonneau Cover Improve Gas Mileage?

Do Tonneau Covers Save Gas?

One of the reasons that you might be looking for a tonneau cover is the claim that tonneau covers save gas. So I know you are wondering,”Is it really true?”

SEMA’s Study

SEMA, Specialty Equipment Market Association uses a study of drag that was made in 1997 by Todd J. Ortolani and Vanwijak Ewosakul at Western New England College’s Department of Mechanical Engineering titled “Improving Aerodynamic Characteristics of a Dodge Ram Pickup Truck.” Basically they discovered that Cd (coefficient of drag) was reduced by 11.81% when compared to a standard model(without mirrors and tailgate up). It shows that the MPG went from 16 MPG for the standard vehicle to 17.18 MPG with a tonneau cover. It may not seem like a large number, but over time this will make a huge difference in your wallet.

 

Mythbuster’s First Study

You would think that SEMA study would prove that tonneau covers save gas, but there was also a study made by Mythbusters to disprove this logic. Mythbusters is a science entertainment TV program hosted by Adam Savage and Jamie Hyneman. In episode 43, they experimented with the tailgate up vs. tailgate down to see which one was more fuel-efficient. They filled up two exact models of trucks and drove up to 55 mph until they ran out of gas. In the end, it was determined that tailgate up was more fuel-efficient because there was a “locked vortex flow” that was made in the bed of the truck that kept faster air from contacting the truck which reduced drag. This episode recieved so much backlash that they revisited this “myth” in episode 64 which is shown below.

 

Mythbuster’s Second Study

In episode 64, they experimented with a hard tonneau cover, tailgate mesh, and the tailgate removed. It was determined that the hardcover used up the same amount of gas at 55 mph as the tailgate up, and that the tailgate mesh got the most efficient gas mileage using an electronic flowmeter that was hooked to the fuel line. So it would seem to be the case that the myth of using a tonneau cover saves gas mileage was busted. More recent studies have shown that their tests are not valid.

 

 If you don’t have a tonneau cover yet, check out our review of the best tonneau covers in 2023 

 

What we Learned

Their first problem was that the experiment did not include different types of tonneau covers. There are other covers that are lighter than the tonneau cover they used. Problem #2 is that they also only tested at 25 and 55 mph, so it would not include how to drag would be reduced at higher speeds or city driving style. If you do a lot of highway driving and use a lighter tonneau cover, it could increase your gas mileage. A soft tonneau cover could pay for itself in no time.

To conclude the argument, some sites say a tonneau cover will save you 10-15% on gas. According to the aforementioned studies, a cover will actually save you closer to 6% based on what type of cover and how you drive. It may be less than expected, but a cover will easily pay for itself over time – especially with rising gas prices. Use the savings calculator below to see how quick your tonneau cover will pay for itself!

We hope this answered your questions about gas savings with a tonneau cover. We are more than willing to answer any of your tonneau cover questions and assist you in picking the right tonneau cover for your truck.

Actual results will vary – this is an estimated savings based on an annual 6% MPG increase.

About the author

David Patterson

Our editor, who brings a wealth of experience in tonneau covers and truck accessories sales to our editorial team. With over a decade in the industry, David has a deep understanding of the products and a knack for helping customers find the perfect fit for their trucks.

3 Comments

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  • “The issue here is that while any tonneau cover can reduce Cd, designs such as painted or heavy duty tonneau covers also add significant weight to your truck, negating any potential mileage improvement. This is why the best tonneau cover for fuel efficiency is a soft roll-up or soft folding bed cover.” In the most scientific test conducted, a wind tunnel test: “On average, using a light tonneau cover led to a 5.7% reduction in drag. That reduced drag meant about a 1.8% increase in fuel efficiency. Even though 1.8% better gas mileage isn’t massive, it definitely makes a difference over a year of fueling up your truck.”

  • You also have to factor in weight of tonneau cover where hard covers tend to weigh a lot more then a soft cover and may not be any better at improving MPG if in fact they even do. In the end the biggest drag on fuel MPG is the front of truck that has to direct air over, under, and around truck. A interesting study done by Cummins on big combination trucks came to conclude that slowing down below 65 could improve MPG’s far more then any aerodynamic additions. Mostly because the faster you go the more resistance you have and the more engine power needed to maintain that higher speed. I think Mythbusters simply proved that spending the money on a tonneau strictly for better MPG probably isn’t going to be worth the investment. But of course many like the styling, and protection.

  • I find it laughable that these cover manufacturers claim the Mythbusters (whom have no skin in the game) testing was flawed when they themselves claim MPG savings without any supporting evidence. How hard would it be for Leer or one of the multi-million$ companies to perform a simple test to prove their claims.. well unless they have already and it proved the opposite. I concur my choice of a cover is based more on security than other factors. Had I worried about fuel economy I’d have bought a Prius.