3 Myths of Truck Aerodynamics

Pickup trucks are not the most fuel-efficient vehicles — and for the most part, they are not meant to be. Most truck owners are more interested in these workhorse vehicles’ ability to haul and tow; their engines should be large and their beds long, their tires wide and tall. Even so, few truck owners want to pay more than they must in fuel costs, which means many truck owners are interested in improving the aerodynamics of their vehicles in any way they can.

Unfortunately, the widespread desire to boost fuel economy and efficiency has resulted in a handful of myths amongst the truck driving community. To learn the truth about truck aerodynamics, read on.

Myth: Tailgate Tricks Reduce Drag

Not only is a truck larger and heavier than the typical city vehicle, but it is not shaped like a regular car, either. Unlike sedans and SUVs, which can slice through the air using a streamlined profile, pickup trucks always have a bulky cab followed by a flatbed. Instead of passing easily over the car, air plummets into the bed behind the cabin and tends to stay there, creating drag that can reduce fuel efficiency.

Over the decades, truck drivers have tried all sorts of tricks with the tailgate in ill-fated attempts to eliminate this drag. One of the easiest tricks is to leave the tailgate down while driving, but drivers might also replace their tailgate with a cargo net or remove the tailgate permanently. In all of these instances, the driver is hoping that the air getting caught in the bed will flow out of the truck, improving the aerodynamics of the vehicle and boosting fuel economy.

Unfortunately, this just isn’t the case. Studies on air flow around trucks have found that with the tailgate properly in place — locked up — air will push down and forward on the back end of the vehicle, helping the back tires grip the road and propelling the truck without the use of fuel. When the tailgate is down or absent, the driver does not have this benefit. Replacing the tailgate with a cargo net is even worse; the net pulls through the air like a fishing net through water, creating even more drag and creating intense inefficiency. This myth is so pervasive that Mythbusters devoted a couple episodes to testing tailgate theories — only to find that drivers should stick with using the tailgate as intended by truck designers.


Myth: Bed Covers Do Nothing

On the opposite end of the truck aerodynamics spectrum, some drivers believe that it is important for air flowing over the cabin to sink deep into the bed. This myth suggests that the walls and tailgate of the bed create a pocket, where airflow creates a swirling ball that repels other air passing over the truck. According to this myth, installing any kind of bed cover will eliminate the beneficial pocket of the bed and worsen fuel economy.

However, research has proven this supposition untrue. Both hard and soft bed covers improve the aerodynamics of the vehicle, encouraging air to slip over the truck without resistance. Even better, truck bed covers do not interfere with the aerodynamic benefit of the tailgate; on a truck with a bed cover installed, air will continue to press down and forward on the back of the truck, but without the drag created inside the bed.

Myth: Running Boards Create Drag

Running boards — also called side steps, side bars and nerf bars — are a popular truck accessory, especially on vehicles that have lift kits installed. These additions, mounted beneath the truck’s rocker panels, make it easier and more comfortable to step into the cabin of the truck, which can make the vehicle more accessible to a wider variety of drivers and passengers. However, some drivers believe that running boards (and similar augmentations) add to the weight of the truck and create drag, increasing fuel consumption.

Unfortunately, this myth could be true — depending on the type of running boards installed. Drivers who prefer the assistance of running boards might opt for steps that are flat and built solidly into the truck’s body, which will allow the air to press down on the boards and improve contact with the road. Drivers can also find running boards that automatically fold out and in when needed, which can prevent any possible drag created by the steps during movement.

Fuel efficiency might not be top of mind when a driver opts for a pickup truck, but it should still be a consideration when drivers select the style of their vehicles. With the right products and practices, drivers can keep their trucks running as efficiently as possible.

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Christophe Rude

Christophe Rude

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