Do tonneau covers improve gas mileage?
Not enough to justify buying one. The most careful owner report found about 5% at best across several covers and trucks, against claims of up to 15%. Buy a cover for what it does for the bed, not for fuel.
On 5thGenRams, a mechanical engineer who has run most cover types (vinyl, roll-up, retractable, and aluminum and composite tri-folds) across several Rams with different cabs, beds and engines reported very little difference, closer to 5% on the best rather than the 15% some makers claim. He added that even 15% would take a long time to pay back the price of a cover.
Other owners in the thread report little or no change. This is one well-informed owner plus anecdotes, not a controlled test, so it cannot set a precise figure. It is still enough to rule out fuel economy as a reason to pick one cover over another, or to buy one at all.
Confidence: single-source · Based on 1 cited source.
Sources
- Tonneau Covers VS MPG Performance · 5thGenRams
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Tonneau Covers: what you're actually buyingBy Purchasd Research. Manufacturer specification, product and warranty pages read directly on 27 September 2026, with list prices taken from the manufacturer or RealTruck.com for the lowest-priced fitment. Corporate ownership traced through the acquirers' own releases, a Moody's rating note, Bloomberg reporting and trade press. Owner evidence comes from model-specific forum threads that could be re-read on 27 September 2026 (Tacoma4G, 5thGenRams, RAM TRX Forum, F150Forum, Tacoma World and the F150gen14 thread database via F150LightningForum). Threads on forums that block automated reading were excluded rather than quoted from memory. 27 YouTube videos were checked against live metadata. Two brands whose own sites block automated reading (Bestop, Rough Country) are sourced to retailer listings and labelled as such. On 1 October 2026, fourteen Reddit threads (r/f150, r/Silverado, r/ToyotaTacoma, r/Tacomaworld, r/gmcsierra, r/ram_trucks, r/FordMaverickTruck, r/RangerRaptor) were found by search and read in full, prioritising long-term ownership, leaks and the shortlisted covers. Not affiliated with any manufacturer or retailer. No affiliate links.