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Tonneau Covers & Fuel Efficiency: The Impact on MPG

Covering your load with a tarp or sheet is a tradition pretty much as old as the pickup truck itself. Ever since the Model T Ford started rolling off the production line, owners have been protecting their cargo using a variety of materials and techniques. The modern answer to this question became popular, and even ubiquitous, in the 1990s with the advent of affordable truck bed covers.

european car tonneau cover

What is a Tonneau Cover?

The word “tonneau” comes from the French language and means “barrel” or “cask”. In early automobiles, the passenger compartment at the rear of the vehicle was often shaped like a barrel and had a removable fabric cover to protect against the elements. 

Over time, the term “tonneau” became connected with the covering or enclosing of the cargo bed in pickup trucks and eventually became the standard terminology for a truck bed cover.

Early tonneau covers were made of canvas or vinyl, but the demand for secure and rain-proof storage led to the adoption of fiberglass, aluminum, and other materials towards the end of the twentieth century. In today’s marketplace, you can find a variety of one-piece, hardshell, folding, or even rollup tonneau covers in all kinds of materials.

03 Smittybilt Smart Tonneau Cover

Aerodynamics & Fuel Efficiency

Installing a tonneau cover on a pickup truck can offer several aerodynamic, fuel efficiency, and stability gains:

  1. Drag Reduction – When your truck is moving, it is punching a hole through the air in front of it, and that air, when displaced, flows over the vehicle, dissipating to the rear. The displaced air creates drag against the truck, and an open truck bed magnifies that aerodynamic drag. Your tonneau cover will reduce the drag produced by the pickup bed and that can improve fuel economy.
  2. Decreased Lift – The top half of your pickup truck has a gentle arc that starts at the front bumper, and ends at the back bumper. The bottom half of the truck has a relatively flat underbelly. Anyone familiar with airplanes knows that this is precisely the shape of an airplane wing, and airplane wings are designed to lift the craft off the ground. Automakers use several tricks to reduce lift and keep the vehicle planted, but one good way to minimize lift is to install a tonneau cover.
  3. Less Turbulence and Improved Stability – An open pickup bed and tailgate create multiple vortices of air when driving, especially at high speeds. These turbulent air patterns can lead to unpredictable handling behaviors, particularly when driving with a crosswind. A tonneau cover drastically reduces the turbulent air and vortices, leading to a more stable drive.

Other factors that can impact the aerodynamic properties of your tonneau cover include the material, design, and workmanship of the installation. Different types of cover may offer varying levels of drag reduction and aerodynamic improvement.

02 BAK Industries BAKFlip G2 Tonneau Cover

Installation Process for Trucks

Every style of tonneau cover will have slightly different installation procedures, so it’s important to carefully read your installation instructions before beginning any installation, but here’s a set of general steps to follow when installing your tonneau cover:

  1. Clean the Truck – Carefully wash and wipe the truck bed, as well as the side walls, so that no dirt or debris is stuck under the installed cover.
  2. Assemble Your New Cover – If your tonneau cover installation instructions call for pre assembly then take the time to put it together before placing it on the truck bed.
  3. Test Fit the Tonneau Cover – Without fastening anything, put the assembled cover in place to see if any adjustments need to be made to the alignment or positioning. You can save a ton of time with this step, by noticing small adjustments that need to be made before bolting the whole thing to your truck.
  4. Fasten Mounting Hardware – Most tonneau covers utilize a mounting system that may include rails or other hardware which is fastened to the truck. Depending on the style of the cover, you may want to leave some of the hardware finger-tight so that you can snug things up when the final pieces are installed.
  5. Install the Cover – Attach your tonneau cover to the mounting hardware and check for alignment before tightening up any brackets or clamps in the mounting hardware. If the cover doesn’t fit at this stage, you may have to back up and adjust the mounting hardware.
  6. Test Open and Close the Cover – Cycle the cover open and closed several times to ensure smooth operation.

Remember to check your installation instructions throughout the process, to make for the best fit possible.


Choosing the Right Cover for Your Truck

If you are in the market for a tonneau cover, pick up trucks have four main styles to choose from. Which one you pick depends on your specific requirements:

  • Folding Tonneau Covers – A folding cover provides a rigid shell that you can place items on top of without worrying about destroying the cover. Usually, the weight rating will be a few hundred pounds or less, but that beats vinyl covers by a long shot. Another advantage is their ability to fold mostly out of the way, although they lose a bit in this area to their vinyl cousins.
  • Retractable Tonneau Covers – A retractable cover has the advantage of being lighter than a folding tonneau cover, while still having a rigid material. It will also be quicker to open and close since the cover retracts into a box at the cab end of the bed. One downside to a retractable cover is the space that the box takes up in the bed.
  • Roll-Up Tonneau Covers – This will be your least expensive option, and because of that it tends to be the most popular tonneau cover that you see on the road. A roll-up tonneau cover is lighter than the other options and doesn’t take up any space in the bed when it is rolled. Affordability and practicality make it a popular choice.
  • Hinged Tonneau Covers – A hinged cover will usually be the most expensive option, but you can color-match it to your truck, and that increases the style factor. If you want the most stylish cover and don’t need to use your bed for hauling large items, then a hinged cover might be the right choice for you.

Whichever style of tonneau cover you choose, you can be sure that it will protect your gear and increase the resale value of your truck! At 4 Wheel Parts, discover a wide range of accessories including tonneau covers to keep your truck efficient and your contents protected.