Seeing very little hard data in the various forums and other places about how a tonneau cover might improve the MPG of a long-box (8'), regular-cab F-150, I decided to build up a cheap hard cover and do some rather controlled testing. I made a lightweight hard cover from some scrap wood, two pieces of the cheapest wood (1/8” MDF, actually) paneling I could find at the local big-box home store, and some bits of hardware. I made the cover in 4 sections so I could get it rather easily on and off the truck, clamping the sections to the bed rails.

I made several runs on open highways where I could control my speed for a few miles without interference, making constant-speed (under cruise control) multiple runs in both directions to take ambient winds out of the equation: at 45, 55, 65, and 75 mph. I used the A trip-o-meter to record MPG, resetting it to zero after the cruise control stabilized the truck’s speed at the start of each run. After averaging the data for each set of runs, it appears that the tonneau cover did begin to improve the mileage starting at about 55-60 mph, but at no time did I see any improvement greater than 0.4 - 0.5 MPG with the cover installed.

The bottom line: I found that (like many of you might readily tell me) a tonneau cover may be useful for protecting your stuff to some extent in the back of the truck, but doesn’t (at least on a regular-cab, long-box F-150) do much to improve the MPG – at least not at speeds up to 75 mph.

So it seems I’ve proved it to myself – given the speeds at which I’ll likely be driving this truck, spending several (or even a few) hundred $$ for a tonneau cover in an attempt to save some petrol and improve the MPG, just doesn’t sound like an economically good idea.

Yes, this is what others have been saying all along – I just wanted to see what the data would look like for MY truck. Can anyone share notably different results? Maybe I did my testing wrong?

 

I bought my X-Tang for keeping snow, ice, leaves and other debris out of my bed, not for better mileage.

The better mileage aspect didn't even go thru my thought process.

 

I like some of the tri-fold soft covers: they go on / come off rather easily, and appear to be able to do a reasonably good job at protection from the elements, and at a good price...

 

They don't help much, but they do help. I didn't buy one for mpg, but I can't deny the added benefit. Less wind resistance means less work, less work means less gas.

If I use your findings and you say you gain .5 mpg by adding it, on a 30 gallon tank, that's 15 additional miles. If we say one tank a week, that's 60 additional miles for the month. If we say you average 20 miles to the gallon, , that's 3 gallons of gas you saved for the month. If gas averaged 4 dollars a gallon, that's $12 for the month you saved. $12 for the month means $144 for the year.

If you are buying the cover for MPG improvements alone, it will take a while for it to offset the initial cost and save you money.

If you are buying it for the purpose of protecting items or you think they look nice or complete the look of your truck, it's nice to know it will pay for itself after a while and eventually save you money.

 

BTW, I have an Undercover. It's pretty lightweight.

Look at it keeping my stuff dry.

 

Here is the formula............

75/20@/^&32/~56/`22= No difference, there ya' go.

 

I bought my cover to also protect the items in the bed. To replace the stuff I carry in the back just once I could buy 4 or more simular hard covers per one disappearing act. So mine pays for it self every time I park my truck!

Plus I like the look.

 

Brand X and an engineering school did tons of wind-tunnel tests on pickup trucks and found that the open bed with the tailgate up isn't quite as bad as it appears. Really a bed cover will just protect your cargo, but at least they don't hurt fuel economy.

 

So it seems. I read through those reports, but I just wanted to run the experiment to see for myself!

 

A real 'myth-buster' would build a full sized wind tunnel (or you could borrow the UofM's) on a tilting dynometer (to simulate elevation changes), inside a vacuum dome (to simulate atmospheric pressure changes) and the whole thang would be housed inside an Anechoic Chamber (http://en.wikipedia.org/wiki/Anechoic_chamber) to prevent any electromagnetic interference to the delicate instruments needed to chart these subtle differences.


But..........I'll take you at your word.

 

Thanks for the info Nimrod, I have a BAK Flip F1 and its a great cover it is very user friendly and keeps everything in the bed protected and if I can save a few bucks on gas here and there that's a plus. Had a one piece Vinyl Extang on old 98 F150, paid less than $ 200 for it on ebay about 4-5 years ago. I liked how it keep stuff dry in the bed of the truck but not really very safe as one cut with a pocket knife and poof everything under the cover would be a goner. So when I bought my new 11 F150 last Oct I researched and found the BAK Flip F1 and love it. Thanks again Nim for the info.
MP
Fort Worth, Texas

 

Well, I went to Ohio from the Washington, D.C. area, and at speeds of 65-75 mph, my Roll-X, in conjunction with premium fuel, netted me 3 mpgs better than prior trips.

And that's running in summer, with the A/C on the whole time, versus winter.

While I also didn't buy the cover for mpgs (mostly to protect luggage), it's been good to me so far.

-John

 

I think they help slightly with aerodynamics, but at the cost of hauling around more weight.

I did it for looks and security on my silver truck

 

If I remember correctly Mythbusters TV show tested pickups with the tailgate up vs down in relation to mileage and there was actually a slightly better result with the tailgate up.

I didn't buy my A.R.E. for mileage gains. It is just really handy to have all that space to store and lock up!

 

I found this little column that had some information from Ford and Dodge engineers. Looks like 1mpg increase is about the best you'll do with a Tonneau cover in the real world.

http://www.trucktestdigest.com/TTDfe...teUporDown.htm

Anechoic chambers just prevent RF signals from reflecting back off the chamber walls. They don't keep them out. Most all sensitive measuring devices are RF/EM shielded to prevent interference anyway. You want an RF Anechoic chamber if you're testing the radar signature of model aircraft, not when testing aerodynamics.