Tailgate up?? or Tailgate down???

[Mundgyver]

Try not to laugh too much at this but curosity can cloud ones thinking. I have heard that Dodge, designed these trucks to get better mileage with the tailgate up rather than down when cruising down the freeway. I have also heard that this is the reason that the back is about 1 1/2 inches narrower than the front. As I said try not to laugh too much. Has anyone out there done a definitive test of the Tailgate up, VS Tailgate down, for mileage?? If so, when and where and what were the results over how many miles??

 

[illflem]

There was an old link I can't find to some university air tunnel tests that showed the increased turbulence with the tailgate down, it was pretty impressive. No mpg numbers though. Tailgate up is the consensus for better mpgs



I always heard the tailgate opening was the only part narrowed to accommodate larger tail lights. Never measured the bed width though.

 

[Sarge]

Tailgate-ing

I have not tested my Ram without the tailgate, but I have tested other trucks that I ahve had with and without the tailgate. The results were there was NO milage improvement without the gate on. There must be something to the turbulance thing. Besides, it looks better with it on!! Sarge

 

[tgbol]

Another interesting fact about air flow over the rear of the bed. a tonneau cover covering only the back half of the bed gives the same result as on covering the whole bed. GMC found this out in the wind tunnel when testing the Cyclone for runs ar Bonneville. They left the front open for access to the ice chest for the intercoolers.

 

[DarrellB]

Got a ticket in my old red Cheby for driving with the tailgate down. Seems it's against the law in Indaina to drive with the tailgate down without a load in the bed of the truck. So know I always leave it up. I don't see were that little wind resistance will effect a truck that wighs 7500lbs.



Big D

 

[Shovelhead]

The wind tunnel test showed that the drag was less with the tailgate on, and down, than the tailgate up.



Maybe someone can locate the link, it had some good pics of the windtunnel tests, and a design for a drag reducing bedcap. (ugly, non-functional, but reduced drag)



edit:

Here's the link

http://mars.acnet.wnec.edu/~ehaffner/did.htm

 

[illflem]

Ed thanks for the link. That was part of what I saw once, think I read the full paper. What your link doesn't say is that the tests and pictures were of a model truck 8 inches high, if that makes any difference.

 

[Shovelhead]

Originally posted by illflem

your link doesn't say is that the tests and pictures were of a model truck 8 inches high, if that makes any difference.

The model also didn't have an Airbulldog hood, 4" lift, monster mudders, and stacks.



If I wanted aerodynamic, I'da bought a Honda.

 

[redneckdr]

drag

just another reason to love my ARE Lo Pro... ... .

 

[Gray Ghost]

Tried it up . Tried it down. Backed into a tree. Couldn't make up my mind which was better, so I bought an aftermarket slotted one. I guess I just split the difference.

 

[Jumbo Jet]

When I was much younger, say 1960 - the tailgate down caused more drag than now. It had four freckled face kids dragging their feet along a gravel road sitting on the tailgate on the way to town.



Can you imagine letting your children do that today??



The tailgate was held up by a rubber covered chain and hook.



My Dad had a 1946, 1961, 1964, and 1968 Dodge trucks when I was growing up. 1961 with 3 on the tree was what I learned to drive. SWB, 225 Slant Six. Mean machine.

 

[Cooker]

If you choose to run with the tailgate down, or without a tailgate, be careful. The tailgate adds to the rigidness of the bed. If you were to run without, or down for many miles the bedsides have a tendancy to get sloppy. Granted it would take many, many miles but I just thought I'd mention it.



My $. 02,

Ryan

 

[klenger]

Jumbo Jet



My dad had the same truck. Windshild washer pump was a bulb on the floor you had to push with your foot to make it squirt. I don't remember that the trucks ever had any problems.

 

[Fast 1]

Cooker is right about the rigidness. The box posts take a beating over the miles without the tailgate. My 97 3500 with over 300,000 towing miles had to have the box corners welded a couple of times. I ran without the tailgate somtimes. I'ts important to check and replace the latch pins for wear if you have alot of miles on the truck. This will keep the tailgate snug and not sloppy. I would keep the tailgate up.

 

[JKloppe]

tailgate

And with the tailgate down, it will get beat up by rocks and road debris.



Jordan

 

[Mundgyver]

Thanks for all the information. The question was worth the asking. Thats what I like about TDR, lots of good information.

 

[klenger]

Do the 5th wheel tailgates provide enough rigidity to keep the box together?



Ken