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ModelE 01-03-2009 01:34 AM

aerocap or tonneau? (build thread?)
hey all-
i've decided to make an aero...something for my frontier's bed.:thumbup:

for the use of mine, mostly 45-55mph with a bit of city driving, whether a tonneau cover or a aero cap would be more beneficial. because i would love to try making an aerocap like bondo and others have, but i think that a tonneau would be a bit easier to make and if the benefits were same/similar then i'd go with that. also, wouldn't a back half-tonneau with something trailing off the back edge of the cab do the same as an aero cap?:confused:

any input would be awesome

aerohead 01-03-2009 01:43 PM

cap vs tonneau
The aerocap,with plan taper gave me 13% at 70-mph with the T-100.A 1/2-tonneau on the same truck was good for 5%.A cab-wing/sailpanel extension of 18-22 inches,combined with the 1/2 tonneau has been shown to up mpg by 9% at 55-mph.I realized this on the T-100.Results are going to vary from truck-to-truck.-------------------------

I spent 200 man-hours on my original cap and never really finished it.You can slam a piece of primed/painted/reinforced plywood across the bed rails for durable proof of concept experiment.( house paint is ok ).

Big Dave 01-03-2009 04:02 PM

My jerry-built fastback fairing, even thogh it is too steep (17 degrees) improved my MPG by 1.5 MPG over a flat tonneau. They do work.

If you haven't the time or skills to make an aerocap, flat tonneaus (hard or soft) are available off the shelf. In fact if you have a Ford Super Duty short bed, I'll sell you one cheap.

festivaWES 01-04-2009 08:47 AM

I's there a specific site to coifecient (sp) drag numbers of different trucks? All if seen on wiki is .60 +or-

MetroMPG 01-04-2009 10:31 AM

Check the "notes" at the bottom of the aero/rolling/power/mpg calculator, here: Aerodynamic & rolling resistance, power & MPG calculator -

There are a couple of sites listed.

ModelE 01-04-2009 07:22 PM

sorry dave, i have a nissan. and my budget is sorta tight so i can't really shell out for a off the shelf tonneau right now. my truck has the TracRac rails on them so i'm wondering how i can incorporate them into the design or whether they make my job easier or harder.

would picking up a regular bed cap and taking a sawzall to it to get it to the aero wedge shape, then taking, say.... fiberglass reinforcements and reattaching it in the aero shape be at all a simple undertaking? or is that more difficult than i think

festivaWES 01-04-2009 08:13 PM

yeah wiki say typical truck .60

TestDrive 01-04-2009 08:38 PM


Originally Posted by younggun (Post 81557)
my truck has the TracRac rails

Didn't know what those are so I googled it. For anyone else reading this thread who wonders what TracRac rails are, here are a couple of pictures.

TracRac rails in use.

TracRac rails only.

ModelE 01-04-2009 08:58 PM

oh yeah, sorry about not clarifying that, sorta figured everyone knew what they are, there's a lot of tradesmen around my area, gotten used to seeing them on every other pickup

metroschultz 01-04-2009 10:36 PM

Thats what you get listening to angry squirrels sing bad songs

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