tonneau covers/mpg

[Nospe811]

We just upgraded to a Keystone Bullet Premier 19 footer that I pull with an 09 gmc sierra 1/2 ton. I've pulled this trailer about 500 miles and have averaged 9 mpg so I am interested in ways to bump the mpg up a bit. I was at a rv dealership yesterday and overheard a conversation in wich a guy claimed he gained 2 mpg while towing by installing a tonneau cover. I was wondering if anyone else has had a similar experience with a tonneau cover?

[Route 66]

2mpg? I'm very skeptical of that.

If that were the case, all of the pick up manufacturers would install tonneau covers as standard equipment as winning the mpg game is paramount to all manufacturers.

[GPW]

Didn't MythBusters debunk that myth ...???

[Chickenman]

I put a cover on my F250 to protect my cargo and it did nothing for my MPG.

[wingnut60]

Mythbusters had a segment on this, seems I remember no positive conclusion. I also remember reading that an auto club or university had tried to prove it would help and could not.
As to my own experience, I have never noted an increase in my 350/450 trucks mileage whether the sliding cover is open or closed. On 2 other trucks, I had fiberglass covers, and the weight of these would have negated any mileage gains.
Get one for security of items in the bed, not mileage...
Joe

[94-Newmar]

Actually the Mythbusters episode did indeed prove that fuel mileage improved slightly (albeit very slightly) with the tailgate UP rather than down. They also tested a tonneau cover, a mesh type tailgate and complete removal of the tailgate. The conclusion and numbers from their website:

• Tailgate down: 5.2 gallons/hr @ 55mph. 1.2 gallons/hr @ 25.
• Tailgate up: 5.0 gallons/hr @ 55mph. No reading for 25mph given, but tailgate up was once again confirmed as more efficient.
• Hardcover over pickup bed: 5.0 gallons/hr @ 55mph. 1.2 gallons/hr @25mph
• Tailgate mesh: same as tailgate up and/or hardcover
• Tailgate removed: about the same as tailgate up and hardcover (80 lb weight differential considered)

This was originally tested on Episode 43 and revisited in Season 4 Episode 64.

[husk]

I put a hard tonneau cover on for security (I have a quiet generator plus other camping things in there)......I hoped for some mpg increase..but I think the added weight lost more mileage than any improved aerodynamics compensated for....

The best way to improve mpg with any rig, is to drop speed. I think there is about 8% increase for dropping 5mph...that is in my car maual in print..and my guess would be the difference should be greater when you're pulling a big surface area like the front of a trailer...

I tow at 50-55 mph, but then I am retired...and for us, the drive is part of experience, and we find a lot of good paved roads off the interstate.