A tonneau cover, also called a bed cover, may improve fuel economy on some trucks, but it is not a guaranteed MPG upgrade. Tests have produced different results, and any benefit depends on the truck, cover design, speed and driving conditions. Choose a cover for its cargo protection and everyday usefulness first, and treat potential fuel savings as a bonus.
What do the tests show?
Consumer Reports tested a 2013 Ram V8 at 65 mph, using an inline fuel meter and runs in both directions. It recorded 22.3 mpg with the uncovered bed and tailgate up, 21.5 mpg with the tailgate down, and 21.4 mpg with a factory soft tonneau cover. In that particular test, the cover did not save fuel. Those results should not be treated as a verdict on every truck or cover.
A 2007 SEMA wind-tunnel report, hosted by Agri-Cover, found an average 5.73% reduction in the coefficient of drag across 13 tonneau covers tested. That is a drag measurement, not a 5.73% MPG gain. The report explicitly called for additional testing to determine actual fuel-economy effects and noted that cover weight and truck design could affect the outcome. As aftermarket-industry research, it is useful aerodynamic evidence, not an independent promise of savings.
Why results vary
Highway versus city driving: Aerodynamic changes matter more as speed rises. Stop-and-go driving adds acceleration, braking and idling, so a highway test cannot predict your city mileage. Do not drive faster to chase a cover's potential aerodynamic benefit.
Cover style and vehicle setup: Soft roll-up, hard folding, retractable and one-piece covers differ in shape and weight. A result for one design on one truck does not establish a universal winner. Cab and bed configuration, tires, lift kits, racks, cargo and towing also make before-and-after comparisons harder.
Tailgate position and test conditions: Tailgate-up, tailgate-down and covered-bed configurations are different aerodynamic setups. Lowering the tailgate is not a reliable fuel-saving shortcut, as the Consumer Reports test illustrates. Wind, temperature, route, speed and measurement method can also change the result. Mixed owner reports are helpful experiences, but they are not controlled comparisons.
Should you buy a bed cover to save gas?
We would not budget for a guaranteed MPG increase or assume fuel savings will pay for the cover. Start with the right fit for your truck's model year and bed length, then compare cargo access, weather protection, security features and compatibility with your other accessories. Browse our Bed Covers collection to compare styles for your setup.
To check your own results, compare several full tanks before and after installation using miles driven divided by gallons added. Keep the route, speed, tire pressure, load and driving mix as consistent as practical, and note weather differences. A small change in a dashboard MPG reading alone is not strong evidence of savings.
Bottom line: A tonneau cover can reduce aerodynamic drag in some tests, but real-world fuel economy may improve, remain similar or worsen. Buy for the cover's practical benefits, not a universal mileage promise.
