Tonneau covers: do they increase fuel economy?

danocross · #1 (**permalink**) 05-17-2008, 02:31 PM

I have noticed more bed cover advertising on here lately. In the past I was always hot to buy a bed cover, but in the end it seemed too inconvenient to not have full access all the time.

Anybody have a bed cover who can pass along verified fuel savings? I have seen them priced from around $500 up to a couple of thousand, so that has to be factored in. I guess in the end, you get one for securing the bed and the contents therein, fuel economy might be a side benefit.

sandmanf250 · #2 (**permalink**) 05-17-2008, 06:57 PM

tests have been done on this subject and it seems no cover and tailgate up was the best.

tex25025 · #3 (**permalink**) 05-17-2008, 08:52 PM

I actually haven't had any loss or gain on mine, but I am now able to use the bed of the truck for luggage and such when on a trip and have more room for stuff up in the cab then before. Since there is no down side for me to having it up(and plus since it's retractable I can move it back) I keep it out unless I'm hauling alot of barn stuff in the bed or hauling with one of my gooseneck trailers.

thedaddycat · #4 (**permalink**) 05-17-2008, 09:34 PM

I read an article a while back that reported on wind tunnel testing and bed covers. IIRC the results showed a slight gain, maybe on the order of 2-3%. I just ordered an Extang RT tool box cover(fits behind a cross over tool box) and tail gate seal. I had been thinking about it for a while, trying to decide on a full bed cover or mount the box and get the tool box cover. I usually run empty but decided to go ahead and mount the box and get the short cover. We'll see how it goes, it was under $400 for the cover and seal. If I see a 2% gain I will have a ROI of about 3-4 years at today's fuel prices.

tex25025 · #5 (**permalink**) 05-17-2008, 09:55 PM

Quote:

Originally Posted by thedaddycat

If I see a 2% gain I will have a ROI of about 3-4 years at today's fuel prices.

It'll start taking you less time to see ROI by the end of the year.

Pocket · #6 (**permalink**) 05-17-2008, 11:50 PM

Quote:

Originally Posted by sandmanf250

tests have been done on this subject and it seems no cover and tailgate up was the best.

Actually yes tests have been done, but you're misquoting the results a tad.

Each brand of truck is different, and even different cab configurations or bed lengths will change the affect. However, it's pretty consistant that just about every truck reduces drag WITH a bed cover.

There's a windtunnel test floating around about a Dodge truck and testing different configurations. Tailgate up, tailgate down, topper, tonneau, cargo net, etc. I believe the tonneau cover reduced drag by a little over 11% in the wind tunnel

Now one thing I did remember about the article is they "guesstimated" fuel economy savings based on the reduced drag. This would be in my mind incorrect, since the physics change when you drive more than 40 mph. However, any reduction in drag does translate into at least some minimal mileage gains.

For most trucks, and typically with Superduties, expect up to a .5 mpg increase in mileage on the highway only with a tonneau cover. Don't expect any gains around town. The .5 mpg improvements is usually a best case scenario.

thedaddycat · #7 (**permalink**) 05-18-2008, 03:40 PM

Quote:

Originally Posted by Pocket

For most trucks, and typically with Superduties, expect up to a .5 mpg increase in mileage on the highway only with a tonneau cover. Don't expect any gains around town. The .5 mpg improvements is usually a best case scenario.

That fits pretty well with what I was talking about. Using a base figure of 18 MPG, a .5 MPG gain is roughly 2.8%. With a base of 16 it is 3.1% and a base of 20 yields 2.5%.

diverseth · #8 (**permalink**) 05-18-2008, 04:27 PM

I have the Leer hard cover and although I love it I don't think it has helped much with the MPG. Maybe 1\2 at best.

JROSCO6 · #9 (**permalink**) 05-18-2008, 10:40 PM

We havent seen any gains on either truck my wifes F150 or my 350.

Lonewolftx · #10 (**permalink**) 05-19-2008, 08:31 AM

There are a couple of threads on this. The MythBusters did a secment on this and found it to be a bust. Try the Discovery website for those numbers.

JJPMach1 · #11 (**permalink**) 05-19-2008, 11:09 AM

they did it on Mythbusters with a f150.

The cover did do the best, but like stated before, the result was insignificant. 2nd best was leaving the tailgate up, the worst was putting the tailgate down.

I bought a cover just to keep the junk in the bed dry when it rains. But I can't be for sure, but, I think the wind noise inside the cab went down when I put on the bed cover.

Lonewolftx · #12 (**permalink**) 05-19-2008, 01:28 PM

I like it as it keeps things locked up, out of sight and dry. Mine is a high grade, Truxcedo lo-profile, canvas model and is easy to roll up when bed is in use and sealed up the rest of the time. Pic's in galery.

smlford · #13 (**permalink**) 05-19-2008, 02:29 PM

I got a roll up hard cover and the best gain I've seen is .3 to .5 MPG in a highway situation. No gains around town but like others have said there are other benefits as well.

thedaddycat · #14 (**permalink**) 05-19-2008, 10:03 PM

Well, I got mine today so I'll probably be mounting the tool box and cover this weekend. It may take a couple of weeks to get even preliminary data(I'll be riding my Harley to work a lot more) but I'll post back once I have anything to report, either of a gain or no gain.

Pocket · #15 (**permalink**) 05-19-2008, 10:19 PM

Quote:

Originally Posted by Lonewolftx

There are a couple of threads on this. The MythBusters did a secment on this and found it to be a bust. Try the Discovery website for those numbers.

Unless they came out with a new episode, the fuel mileage test they did with the F-150 only compared the tailgate up vs down. They didn't do mileage testing with a tonneau cover.