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Old 12-28-2010, 05:51 PM
E.L.D. 44's Avatar
E.L.D. 44 E.L.D. 44 is offline
Dodge Ram Forum Senior Member
Join Date: Dec 2010
Location: Oklahoma City, OK
Age: 33
Posts: 692
Gender: Male
Vehicle: 2011 Dodge Ram CC 4x4 Sport
Trim Level: Sport
Color: White
Engine: 2009-???? 345ci (5.7L) Hemi V8 390hp 407lb/ft
Rep Power: 5
E.L.D. 44 is just really niceE.L.D. 44 is just really niceE.L.D. 44 is just really niceE.L.D. 44 is just really nice

Okay, I'll shed some light, just don't make fun Of me for knowing this. Lol

A truck with the tailgate up is already a pretty efficient design. As air comes over and around the cab it dives into the bed and as it hits the tailgate it diffuses backwards and then up the back glass like a big circle. Kind of like a high pressure/low pressure system meeting in weather terms. This is why you see trash in the bed make it's way towards the cab and go up and down. It's catching the funnel effect of the air. This doesn't create a whole lot of drag and therefore no significant mileage loss. You may get a hair better mpg from a cover due to even lower drag but not much. Despite popular opinion having the tailgate down or removed actually hurts your mpg due to this principle.

Hope this helps...
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