More mileage. with shell and without?

[Arborigine]

Has anyone done fuel mileage comparison with and without a shell over the bed on the same truck?
Since i have no 5th wheel and a big slide-out in the bed I am thinking of leaving the shell on through the winter.
I would guess a shell should give better aerodynamics, but the thing is a slow brick to start with, and an open bed does create an air bubble effect.

 

[franklin2]

Any gains or losses would depend on your driving habits. If you do not do any high speed long trips, then there is no point in worrying about it. Also, if you do not have a overdrive tranny, there is no point worrying about aerodynamics. The engine will be wound up so tight, any aero losses are not noticed.

 

[sle2115]

Saw mythbusters episode where they did all kinds of tests with all kinds of changes...nothing seemed to improve mileage much. In fact, the tailgate up, no shell (open bed) was their best mileage run. The added weight would probably account for some of the tests, weight offsetting any minimual aero gains.

 

[mariner45]

I feel the shell does make a difference - though I haven't done any studies on it.
My canopy stays on my truck all the time except when I need an open truck bed to carry stuff. I like the fact that the bed then stays clear and clean of weather related conditions (rain, snow or ice) .

Just my opinion of course - and just like rear ends, everyone has one

mariner

 

[MIDNIGHT RIDER]

I must have saw the same episode sle2116 spoke of, as I remembered seeing it somewhere.


I also read a magazine article somewhere that shot down the tail-gate-down myth; mileage was actually a bit better with the tail-gate closed.

They even did a comparison with one of those open nets versus a closed tail-gate and the closed tail-gate won again.



I am sure that results would vary between body-styles and some makes might have opposite results.




As for the topper, I doubt one would notice fifty-cents a week either way in the real world.


It is worth a lot in rain-soaked Kentucky to have a dry place to haul feed, groceries, Christmas presents, and such.

 

[TWeatherford]

It certainly will have an effect, however the difference I think will be so small that it would be impossible to tell if it was helping or hurting. So many factors play into it that its hard to dial in on one variable. I'd do whatever is most convenient for you.

 

[Michael Fowler]

Getting old sucks.
I remember reading, but don't remember where, the results of a study done by Ford, I think on this very topic. The study showed that solid tailgate, closed caused the formation of some sort of aerodynamic "swirl" that improved airflow versus all other conditions.
Think of it this way--If a mesh tailgate, or bed cover or anything would result in a measurable increase in efficiency, don't you think the manufacturers would be all over it? With CAFE standards being what they are, they need any increase they can get. They redesign the mirrors, for goodness sake, just to gain a tenth of a mpg---don't you think they'd revise the tailgate if it helped.

 

[RLDSL]

Getting old sucks.
I remember reading, but don't remember where, the results of a study done by Ford, I think on this very topic. The study showed that solid tailgate, closed caused the formation of some sort of aerodynamic "swirl" that improved airflow versus all other conditions.
Think of it this way--If a mesh tailgate, or bed cover or anything would result in a measurable increase in efficiency, don't you think the manufacturers would be all over it? With CAFE standards being what they are, they need any increase they can get. They redesign the mirrors, for goodness sake, just to gain a tenth of a mpg---don't you think they'd revise the tailgate if it helped.

Very good point. If they could claim a tenth of a mile per gal off it, they would sell trucks from the factory without a tailgate and then sell you the tailgate as an option so they could claim the mileage figure, obviously they havn't come to that conclusion. COnsidering the lengths they go to to get the mileage figures that they do get that nobody ever sees in the real world, they would have jumped on it if it were a possibility.
Heck, just to get the unreal figures that they do get, I love the methods they use ( and somehow are allowed to get away with ) They run on a closed banked oval track at either 55 mph or a mixture if speeds under 35 on special tires that have a tread in the middle that is only about 1/4" wide and the tires are filled with 200psi of nitrogen to maintain stability and almost zero rolling resistance. they run the things around and around without stopping and come up with the figures, so yes, they actually did get those unreal mileage figures out of that vehicle you bought , but never see the same kind of mileage, they just have a lot of loopholes.

 

[Diesel_brad]

here is one for ya.
Not a ford but still a crewcab pickup

my neighbor has a 07 Toyota Tundra. Older guy in his late 50s.
Anyway. The truck always has a tonno cover on it and he gets a consistent 18-19MPG. The tonno cover got a big rip in and and since money is tight, no money for a new one. The past 8-10 tank loads of fuel he has been getting 21MPG with no tonno cover and tailgate down.

EVERY truck is different so YOU need to find out what best works for YOUR truck and driving style

 

[GenLightening]

It also depends on how much snow you get over there in the winter. If the bed is filled with it then you're carrying around quite a bit of extra weight.

 

[OLDBULL8]

Don't know about you guys and tailgates, but I get better mileage with my tailgate on as opposed to having my flowthru tailgate on when I wasn't pulling my 5er. To each his own.

 

[jhnlennon]

I know on my f150 I would lose almost 2 mpg's hwy with the shell on than with it off. I routinely checked it as I always noticed a differance in power with it on. Again this was on a f150 with a straight 6 and 3.08 gears.

My toytota's were the same story, big differance...

 

[lotzagoodstuff]

My truck is definitely worse with the camper top on it, which is interesting, because my buddies 2007 F350 CCLB 6.0 Powderchoke got 1.5 miles per gallon better when he put a soft tonneau on it. Go figure

 

[Arborigine]

I saw the Mythbuster's test and think their "research" is not reliable or long enough to be meaningful. I had previously heard of the bubble idea, you can see it when you drive off with a bed full of leaves.
Nothing beats the results of someone who has driven thousands of miles both ways with the same vehicle over the same roads.
As for the weight of snow, not a bad thing, but the dog would prefer to ride under the shell. I put 4-6 sandbags full of gravel in the back of all our vehicles for winter, but not sure yet if this 3/4 ton will need much more than a full rear tank for traction. Spilled gravel is easier to clean up than sand and can be used for traction.
We are discussing driving it 1000 miles to Colorado for Xmas, Vs the wife's Cherokee, I think the truck may get better mileage when both are loaded, but too soon to tell.

 

[Diesel_brad]

For a 1000 mile trip there is no doubt in my mind, I would put the cap on