Improving the gas mileage of a truck isn’t as easy as it sounds. Tonneau covers claim to work wonders with a truck’s gas mileage. But do tonneau covers save gas?
Yes, in theory, tonneau covers improve the overall aerodynamics of a truck which should lead to gas mileage improvements.
But there are more factors in play than it meets the eye, and in this short guide, I will break down exactly how tonneau covers work.
I will also discuss whether or not they actually save gas and how much improvement you can expect with tonneau covers.
What Is a Tonneau Cover?
Now, before I jump into the details of how tonneau covers work and affects the gas mileage, you should understand what tonneau cover is in the first place.
As the name suggests, a tonneau is a cover that covers the back of your truck. Their sole purpose is to cover the back of the truck bed and ensure the components that inside remain safe.
They also act as a concealer that ensures that air doesn’t drag your truck when it is in motion, which makes the truck move smoother and faster.
Thus, ultimately improving the overall gas mileage of your truck.
How Tonneau Covers Improve Gas Mileage?
As mentioned earlier, tonneau covers improve the gas mileage by ensuring that the air doesn’t drag the truck down when it is in motion.
This is because when you put a tonneau cover on your truck and put the tailgate up, you are completely blocking that area. That is, air can’t get inside the locked truck bed.
Now, aerodynamically this means the force of air won’t drag the car down because there isn’t something for the air force to come in contact with in the first place.
As such, there is no air resistance, and the car covers more distance in a shorter amount of time and fuel.
If there wasn’t a tonneau cover then the truck bed or the back of the truck with tailgate up will be similar to a vessel or bucket that is grabbing onto passing air as long as the car is in motion, thus making the engine work harder.
But with tonneau cover, this isn’t a problem. Therefore, the engine works less hard, meaning a steady improvement in gas mileage.
Do Tonneau Covers Actually Work?
Now, how do tonneau covers fare in real-life practical situations?
I have done tests on my truck and visited a few other popular reviewers like the popular MythBusters TV show to find out their results as well. So, let’s take a look at them, shall we?
MythBusters Experiments & Findings on Tonneau Covers
MythBusters is arguably one of the most famous mad scientists of the early 2000 era. They did vehicle-related tests and experiments on popular tricks and items to find out whether they actually work or not.
In MythBusters episode 64, they have tackled the issue of the tonneau cover and whether they have any impact on gas mileage increase.
They did the test with the tailgate down and up, mesh tailgate, no tailgate & tonneau covers.
Their truck ran a steady 5 miles with a constant speed of 55 miles per hour with the mentioned attachments.
Upon finishing the test, they found that with a tonneau cover, the car ran 5 gallons per hour which were slightly better than no tailgate, which was 5.2 gallons per hour.
My Findings on Tonneau Covers
From both my personal experience using tonneau covers and other reviewers, I can state that tonneau does increase the overall gas mileage of a truck.
That being said, there are a few factors that come to play in deciding that. And they are:
Weight: The weight of your tonneau plays a major role when deciding the gas mileage. Because if you pick a heavy tonneau cover, you will add up on the overall weight of your truck and this will make your engine work much harder than before.
So, you might not even notice any change in gas mileage because while the tonneau is working, the heavyweight is still dragging the gas mileage down.
In the worst-case scenario, picking up a heavy tonneau cover that is far heavier than your car’s capacity can bring your gas mileage to an all-time low!
Driving Speed: Speed maintenance is also a factor that impacts gas mileage. Highway speed and stopping and starting are completely different. At average speed, the gas usage will be low.
So, higher speeds will only mean high gas usage, so your tonneau cover can’t really do much to prevent that now, can it?
Mismatched Configuration: This is quite rare, but if you are using a tonneau cover that isn’t a proper fit for your car, then there won’t be much difference in gas mileage, to begin with.
Now comparing all of these factors, I can say that tonneau covers do improve your truck’s gas mileage, but it highly depends on getting the right tonneau cover for yourself.
That’s why Consumer Reports  also suggests you pick up a tonneau cover to improve your gas economy.
So, How Much Gas Do Tonneau Covers Save?
This is a debatable question to answer. As some drivers have witnessed a drastic improvement in gas mileage while others have not so much.
But if I have to point out a number, then I would say that with tonneau covers, you will witness a 2-10% improvement on your gas mileage.
This, with all the other benefits that come with a tonneau, does make it a must-purchase for your trucks!