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When loading the trailer (24x8.5) Monday to return back from Autobahn (what a great track(s)) we forgot to put our portable flooring (4x8 sheetys of laminated plywood) in the trailer before the bikes
. So we loaded them in the bed of the truck instead. I have a 6' bed so they stuck up like a ramp on the tailgate. Without thinking about gas milage I departed for home.

Check these numbers out.

I get 350 miles out of a tank commuting to and from work

I get about 275 miles out of a tank when towing the trailer (I drive 75mph)

On the way back from the track with the plywood in the bed I got 360 miles out of the tank!

Maybe all those guys with Honda Civics with 4' wings actualy know something
(just kidding)
 
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Discussion Starter #2
Does anyone have a recommendation for a loading ramp they like? I have a Dodge Ram 4x4 that I would like to put the bike in, but when I call around everyone says my 749 would scrape on a ramp if I didn't have it backed up to a hill or something. Being a 4x4, the bed sits a little higher than most trucks.
 
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Re: Gas Milage (section8superbike)

i'm thinking the wood acted as a wing to help direct the air up and over the trailer front, thusly reducing the aerodynamic drag. kinda like the diflector guys towing 5th wheels have on the cab roofs to help get the air up and over the exposed front of the trailer.
you've got a 250, right? i'm semi thinking of a 350 with duellies right now. i want the biggest ass truck on the road
 
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Re: (georgeb)

I have two ramps that I use on my F150 4x4. I set them up 1-2 ft apart, the bike goes up one ramp and I walk up the other. The ramps are adjustable for length from 5 to 8 ft and bowed in the middle so I don't have clearance problems with the bikes but my riding mower drags.

On level ground it takes 2 bodies to get it up & down the ramps. I have a rise in my yard that I back up to so I can load and unload by myself. These ramps work ok but one of those 2-3 ft wide metal ramps would give more area for better footing- especially in the wet. Might have clearance problems with a straight ramp though. I've been thinking of getting a trailer so I can use the bed for hauling misc stuff to track days and not have to hassle with ramps .
 
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Re: (duc97sp1)

Did you get lucky and gas up somewhere they don't have that cursed MBTE or alcohol gas?

My car gets 3-4 mpg better on real gas.
 
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Re: (duc97sp1)

Oops... I hit the send button before I finished. Think of the tailgate as flaps on an airplane. Full flaps upon landing provides great drag. Tailgate up also creates the same (a lot) of drag.

Next trip leave the tailgate at home. You'll likely see the same mileage improvment.
This trip the plywood did the same thing, directing the air flow over the giant speed brake called the tailgate.

Although impractical, the best air flow would be gained by attaching the plywood at the back top of the cab, and letting it slope down into the bottom of the bed. This would really smooth out airflow and reduce turbulence.

Remember those webbed tailgates made out of tie down material people used? Remember how they bowed out when the pickup trucks went down the highway?
I always laughed. That open hole design is used in drag chutes on fighter aircraft. One of the claims the manufacturers used was that their product offered less drag hence better mileage. I gotta call bullshit on that claim! That design makes more drag than a standard slab of steel tailgate.
 
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Re: (Old Fart)

I read an article about a couple of wind tunnel engineers at Boeing with a little spare time who decided to solve a certain urban myth. They put a full size (I think Ford) pickup in the tunnel and got a lower cD with the tailgate UP.

the theory is that with the tailgate up, a mass of rotating air in the bed acts as a de facto aero device that assists the air up and over the truck. With the tailgate down, a low pressure area is created behind the truck, thus increasing drag and decreasining mileage.

http://www.truck-bed-covers.co...l.htm
 
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DesmoBob: Saw a similar counter-intuative report as well. Here "ruff" scales on fish scin actually create less drag than completely smooth surface. Due to similar small circular fluid flows that are created by the scale texture, it actually creates a small surface of high pressure around the fist creating a secondary "slipperier" surface for the oncoming fluid to flow against. Given this research I would expect F1 cars to be wearing scales in the next couple of years......
 
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Re: (DesmoBob)

All I know is when I look in the mirror at my tonno cover at speed, the last 1/3 near the tail gate is being pushed down really hard. The tail gate is nothing more than an air brake with a drag coefficiency of 1.0. I get noticeably better mileage with my bed covered, no question.
 
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