Tonneau cover and mpg

[Beowulf85]

Anyone notice much of a difference in mpg when useing a tonneau cover? If so how much?

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[ShadowsPapa]

Anyone notice much of a difference in mpg when useing a tonneau cover? If so how much?.

I did with my Chevy - that's one reason I went with one on that truck because of what I heard from others - and then later found for myself. It wasn't a huge amount, but I did note it was better with it, and closed. Tail gate catches a lot of air.
Not sure about the shorter smaller JT tailgate - the box is shorter, closer to the back of the truck, the box is more narrow...........

 

[Beowulf85]

I did with my Chevy - that's one reason I went with one on that truck because of what I heard from others - and then later found for myself. It wasn't a huge amount, but I did note it was better with it, and closed. Tail gate catches a lot of air.
Not sure about the shorter smaller JT tailgate - the box is shorter, closer to the back of the truck, the box is more narrow...........

Awsome thanks for the input. You think it was 1 mpg at least?

 

[ColoradoGlad]

Anyone notice much of a difference in mpg when useing a tonneau cover? If so how much?

As far as looks, Thumbs up
As far as being utilitarian, Thumbs up
As far as keeping items out of sight and dry, Thumbs up
As far as improving MPG, Thumbs down Absolutely no difference.

 

[Beowulf85]

As far as looks, Thumbs up
As far as being utilitarian, Thumbs up
As far as keeping items out of sight and dry, Thumbs up
As far as improving MPG, Thumbs down Absolutely no difference.

Damn lol . thanks for your your input

 

[ShadowsPapa]

Awsome thanks for the input. You think it was 1 mpg at least?

It's been a while, but I suspect that was about right when on the highway. Not anything real in town and bumming around locally, but the highway, I noticed a difference.
Some guys replace the tailgate with the mesh type or something more open. Like I say, not sure on the JT but a full-sized truck on the highway, it matters.

 

[MarineHawk]

Tail gate catches a lot of air.

Mythbusters had an episode where they purported to dispel that as a myth. They didn't compare gate-up vs. tonneau cover. But they compared gate-up vs. no gate. And the gate-up mode got better MPGs. I think the theory is that, at high speeds (the only ones that would matter), there is a rotating high-pressure pocket of air in the bed, and almost all of the air streaming over the top just rides over that. whereas, with the gate off, the air drops into the bed and below it after that, which actually was less aerodynamic. A tonneau cover should be at least as aerodynamic as an empty bed, if not a little bit more, but the gate catches very little air. One time, almost 30 years ago, I drove my 2-seater Ford Ranger from Albuquerque to Lawrence, KS with some unprotected small electric appliances my dad gave me in the bed. During the last hour, when I was going between 60 mph and 70 mph, I entered an insane torrential rainstorm. I was thinking: Oh well, so much for those items. When I got home, after passing out of the storm, I looked in the bed, and there was not a single drop of water in there.

 

[Beowulf85]

It's been a while, but I suspect that was about right when on the highway. Not anything real in town and bumming around locally, but the highway, I noticed a difference.
Some guys replace the tailgate with the mesh type or something more open. Like I say, not sure on the JT but a full-sized truck on the highway, it matters.

Mythbusters had an episode where they purported to dispel that as a myth. They didn't compare gate-up vs. tonneau cover. But they compared gate-up vs. no gate . And the gate-up mode got better MPGs. I think the theory is that, at high speeds (the only ones that would matter), there is a rotating high-pressure pocket of air and almost all of the air streaming over the top just rides over that. whereas, with the gate off, the air drops into the bed and below at after that, which actually was less aerodynamic. A tonneau cover should be at least as aerodynamic as an empty bed, if not a little bit more, but the gate catches very little air. One time, almost 30 years ago, I drove my 2-seater Ford Ranger from Albuquerque to Lawrence, KS with some unprotected appliances my dad gave me in the bed. During the last hour, when I was going between 60 mph and 70 mph, I entered an insane torrential rainstorm. I was thinking: Oh well, so much for those items. When I got home, after passing out of the storm, I looked in the bed, and there was not a single drop of water in there.

That's crazy thanks for sharing.

 

[ShadowsPapa]

Mythbusters had an episode where they purported to dispel that as a myth. They didn't compare gate-up vs. tonneau cover. But they compared gate-up vs. no gate. And the gate-up mode got better MPGs. I think the theory is that, at high speeds (the only ones that would matter), there is a rotating high-pressure pocket of air in the bed, and almost all of the air streaming over the top just rides over that. whereas, with the gate off, the air drops into the bed and below it after that, which actually was less aerodynamic. A tonneau cover should be at least as aerodynamic as an empty bed, if not a little bit more, but the gate catches very little air. One time, almost 30 years ago, I drove my 2-seater Ford Ranger from Albuquerque to Lawrence, KS with some unprotected small electric appliances my dad gave me in the bed. During the last hour, when I was going between 60 mph and 70 mph, I entered an insane torrential rainstorm. I was thinking: Oh well, so much for those items. When I got home, after passing out of the storm, I looked in the bed, and there was not a single drop of water in there.

Wish I could say I had the same experiences. I found differences in my F250 8' bed compared to the Chevy 6'.
The Ford had a spot behind the cab where you could toss things and they'd not blow out. The back half- you'd better have had it strapped in and covered. I watched boards blow up and out the back. Lifted right up like they were floating, then out.

The Chevy lost stuff in any part of the bed. Even up front, unlike the Ford. If there was anything in there to keep dry - you covered it.
I noticed more drag when I had to have the cover rolled up because of something in the bed just enough to stick up against it.

 

[ALVagabond]

The less cohesive the stream, the less aerodynamic the airflow.

 

[ShadowsPapa]

It would seem that a short box vs. long box would matter.

I wonder how my car with the roof spoiler would look in a wind tunnel. Or my car with the duck tail spoiler.........

 

[Bobzdar]

Zero difference.

 

[MarineHawk]

It would seem that a short box vs. long box would matter.

Right. All what I said above was for a fairly-short box. A longer box would have different dynamics.

 

[MarineHawk]

The less cohesive the stream, the less aerodynamic the airflow.

That's what I was talking about, though I didn't have the pics to support it.

 

[MarineHawk]

The Ford had a spot behind the cab where you could toss things and they'd not blow out. The back half- you'd better have had it strapped in and covered. I watched boards blow up and out the back. Lifted right up like they were floating, then out.

How many people behind you did you kill or seriously maim during this experiment? It's possible that they were a-holes; I hope so.

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