We hear this question a lot. Anybody with access to the internet and an hour to kill can probably find an answer, but which answer, and whether it’s the right answer could be anybody’s guess.
We would not be the first to try to summarize the research on tonneau cover gas mileage. All research we found has been focused on one college engineering study, an episode of the MythBusters TV show, and a wind tunnel study. Based on this information, to the question, does a tonneau cover increase MPG, the short answer is yes.
It’s all about drag. Generally, anything that reduces the drag on a vehicle while it’s going down the road will improve its fuel efficiency. Does a bed cover improve gas mileage? It does if it reduces drag.
A 1997 Western New England College study using a water tunnel resulted in an award-winning paper written by the engineering students who performed it. They concluded that Tonneau covers reduced drag by nearly 12 percent. So, does a tonneau cover improve gas mileage, or does a truck bed cover save gas? According to this study, by reducing drag, it does save gas and improve mileage.
But a 2006 episode of the popular science-based show, MythBusters came to a different answer. They performed experiments at 25 and 55 miles per hour and monitored actual gas consumption, and concluded that the fuel usage of their truck was “about the same” as an open truck bed with the tailgate closed or with it removed. Notably, from a mileage standpoint, they found a mesh tailgate to be slightly more fuel efficient, and an open tailgate to be the least fuel-efficient option. Based on this experiment, does a tonneau cover save gas? Maybe not much under the conditions they tested.
Lastly, in 2007, the Specialty Equipment Market Association (SEMA) conducted a series of wind tunnel tests on several models of pick up truck, using wind speeds of 30 to 85 mph. In their report, SEMA detailed their procurement of test covers and test trucks, along with the testing procedures and the math they used to calculate the coefficient of drag, and then compared it to the baseline coefficients of drag for each truck with an open bed and tailgate up. While there was variation based on cover type, truck model, and wind speeds used, they concluded that, on average, “it is safe to say that a tonneau cover will reduce the coefficient of drag by 5.73%.” Will a tonneau cover improve mileage if it reduces the coefficient of drag? Again, the answer must be yes.
It’s tempting to give the MythBusters test a lot of credence as the only one that actually put a truck on the road and measured fuel consumption. Water tunnels and wind tunnels are isolated simulations, not where the rubber meets the road and the fuel is consumed. But MythBusters is a case study using one model of truck on one stretch of road, with a couple of guys taking a few data points. It could be called scientific research, but its small scope leaves a lot to be desired.
So asking, do tonneau covers help MPG for your truck, may be too narrow a question to be useful. We find most people want the a truck bed cover to keep all of their cargo safe and secure without worrying too much about strong winds, rain, and opportunistic thieves from taking advantage of an open pickup box. If the only reason you’re considering buying a tonneau cover is to improve your gas mileage, you would be satisfied to know that it will most likely help a little, and maybe even pay for itself in the long haul. That said, chances are good that you’re investigating tonneau cover options with the hopes of finding a bed cover that will also provide you with security, flexibility and protection.
Configure a bed cover for your truck and learn more about the Peragon truck bed cover.
Sources and Notes:
Auto’s Need https://autosneed.com/do-tonneau-covers-really-save-gas/
MythBusters actual episode on youtube: https://www.youtube.com/watch?v=r3aqHbD-O9E
1997 Western New England College study source: http://web.archive.org/web/20030414190338/http://mars.acnet.wnec.edu/~ehaffner/did.htm
Write a Comment