Tonnau Cover on new truck saves Fuel?

[CdnRanger]

Bought a new 2014 Toyota v6 dbl cab 4x4 - I am thinking of getting a tri-fold hard Tonnau cover for it and was wondering if anyone noticed better mileage from having one on their Tacoma or any other pick-up truck?

Thanks -
CdnRanger

[theholycow]

I suspect that it won't help. Data that I've seen before usually shows that it does not help. They are designed and tested with no cover after all.

Of course if you wanted to do something more extreme, you could do something like this:
http://www.fuelly.com/forums/showthread.php?t=13149

[trollbait]

It seems only available behind a pay wall, but the National Research Council of Canada did wind tunnel testing of pick up tailgates. The short form of that is to keep in up for most trucks.

They also looked at a partial tonneau cover. Why partial? Because GM had a patent on the use of a partial one because helps with aerodynamics. I had one on the Ranger because of this paper. Can't say how much it helped at this point since the data is gone, and I no longer have the truck.

So tonneau cover will improve aerodynamics. Depending on the commute, that might not equate to improved fuel economy. Even then, the efficiency gains likely won't cover the cost of the cover. If you want to cover the bed for other reasons, it can be a bonus.

Article on the paper:http://www.nrc-cnrc.gc.ca/eng/achiev...down_myth.html
The paper source: http://search-recherche.nrc-cnrc.gc....ofile=_default

[CdnRanger]

Thanks guys, I'm going to get one soon and will see if it changes anything - I was going to need one anyways so it would be great if the mileage stayed the same at least -

Cheers!

[trollbait]

Never heard of them making fuel economy worse.

For trivia, only trucks with non-crew cabs and 8ft beds benefited from having the tailgate down. Then aero improvement is so slight it might not equate to economy improvement for most driving.

[evilspoons]

I know this thread is old now, but testing has been done by multiple sources that says a complete bed cover makes fuel economy worse (so does removing your tailgate with an open bed). I think there was a Mythbusters epsiode, and a government agency of some sort did some testing, and then Ford showed off their new F-150 with some wind tunnel testing with Autoblog.com.

Here's the Autoblog link: http://www.autoblog.com/2014/08/26/f...own-mpg-video/

Virtually all trucks behave the same way as the Ford in the video in spite of no fancy spoiler specifically designed to reduce drag; it's something to do with a pressure zone being created in the truck bed that deflects air OVER the truck instead of maintaining turbulence while you drive.