Bed cap and fuel mileage?

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Ramconvert

Active Member
May 25, 2015
169
52
28
Pewaukee WI.
Truck Year
2015
so I'm most likely going to order a truck cap. The only thing giving me pause is a friend of mine claims his cap lost him at least 2 mpg's.

I don't know how much I believe this?? I suppose it's possible but wanted to hear from some others with the ED.

So if you've installed a cap did it affect your MPG either good or bad?

For the record I've always had soft covers. They either helped very slightly or had no effect on fuel economy what so ever.
 

BoostN

Administrator
Staff member
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Jul 27, 2013
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Tennessee
ecodieselram.com
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I don't have one so I can't really say, but I've also read of folks loosing mileage. I don't see how it could hurt fuel mileage in my opinion.
 

moparecodiesel

Active Member
May 24, 2015
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I love my bedcap, its the cheapest one I could find, but it was super easy to install and it is so convenient, and no I did not lose any mpg, however when I hooked up my trailer without the tonneu, I lost more mpg without it, but with the trailer and tonneu in place I kept my mileage. With the trailer hooked up and the open bed the turbulence is crazy back there, you can tell because you can drive with your rear window open and things start flying inside your cab hitting you and blowing dirt inside, but with the tonneu covering the bed, nothing comes inside, you don't hear any wind violence in the back, and its very nice and smooth sounding back there. Now with the ramboxes our tonneus are very expensive and harder to find, with the straight bed like yours you have many many more opotions and you can find an ok tonneu for as little as $200. where mine was $500 for the cheapest one available.
 

Ramconvert

Active Member
May 25, 2015
169
52
28
Pewaukee WI.
Truck Year
2015
@moparecodiesel.

Thank you for taking some time to answer my question. I've actually noticed a slight improvement in mpg with my trucks in the past. But with this truck I would like to put a cap on,not a tonnue cover.

While I like the look of a tonnue much better. I need a place for my dog. He's a 10 year old Australian shepherd. Very furry fluffy and shedding dog. So I want a comfortable place for my four legged little buddy that's NOT in the cab with me. Lol. Plus there would be some other advantages for me to have a cap instead of a tonnue.

All my experiance has been with tonnue's. Like I said, I've seen slight improvements with tonnue's. I've never had a cap and have read both improvements and decreases in mpg with caps. Some even say no difference either way. I'm not sure what to believe.

I'm most likely going to put one on either way as it has a lot of up sides for me so maybe it will be a time will tell sort of thing.
 

moparecodiesel

Active Member
May 24, 2015
278
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43
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oh with a cap I get a solid 2mpg increase in mileage every time when im pulling my trailer, I love caps, in fact if there was one available for the ramboxes id do it in a heartbeat. What ive done is set up some cardboard boxes in my bed and stacked them on my ramboxes so it is the exact same shape as a campershell and done the math and tests. but with no trailer and just the truck I didn't see any mpg gain or loss. The only thing that I think you might have any loss in mileage from would be from the weight of the fiberglass shell, but that would be minimal. I liked the weight of the aluminum shells but I liked the looks of the fiberglass shell. I love shells, I put them on every truck I own.
 

Ramconvert

Active Member
May 25, 2015
169
52
28
Pewaukee WI.
Truck Year
2015
oh with a cap I get a solid 2mpg increase in mileage every time when im pulling my trailer, I love caps, in fact if there was one available for the ramboxes id do it in a heartbeat. What ive done is set up some cardboard boxes in my bed and stacked them on my ramboxes so it is the exact same shape as a campershell and done the math and tests. but with no trailer and just the truck I didn't see any mpg gain or loss. The only thing that I think you might have any loss in mileage from would be from the weight of the fiberglass shell, but that would be minimal. I liked the weight of the aluminum shells but I liked the looks of the fiberglass shell. I love shells, I put them on every truck I own.

Sure. That makes sense. I can see a few hundred pounds adding a little bit to city mpg. A friend of mine has an f150 (poor guy) with the 5.4 He insists he lost about two mpg with his cap. He gets about 17 with his truck. He said before the cap he could get close to 20. These are figured with fill up devided by mileage though. IMO this isn't very accurate.

Thanks for the info!!
 

jdn112011

Well-Known Member
Oct 18, 2015
1,202
310
83
27
Roseau, MN
Truck Year
2015
I put a leer high rise on and barely lost any mileage. Tonneau wasn't a noticeable difference but I installed it after the 6 hour drive home the day I got my truck.

Leer 122 I maybe lose 1MPG straight driving but I still match pretty well to what I was at.

But a head or cross wind, I do feel the punch. But I was very sensitive to head winds before. It's just a little more pronounced with the huge profile now. Still maybe 3MPG loss highway with wind. Vs 1-2 consistent without the cap.

I wouldn't sweat it you're still beating anyone else out there.

And as Shawn said, towing anything high profile a cap does wonders