I have seen many videos that the tailgate being down doesn't do anything for air flow on the newer trucks. They show the air flow going over the tailgate because of the cab. While taking off my Mom's trash, I put 2 big black bags, one on the right side and one on the left side in the back touching the tailgate. I put a small white trash bag in the middle next to the tailgate. While driving around 45-50 mph, all three bags were being hit hard by air flow, from the bottoms of the bags to the top. I watched very closely in my rearview mirror. Maybe the new trucks cab is high enough for the air flow to clear the tailgate but I know for a 'fact' on my 1991 the air flow is hitting my tailgate, Hard......

Just wanted to share.............Have any of you tried this?

 

Has nothing to do with the model year, although some newer designs may be more fuel efficient.

Myth Busters - The Myth: Driving with your pickup truck's tailgate down is more fuel efficient than driving with your tailgate up. Additionally, driving with no tailgate at all, with a hard cover over the pickup bed, or with mesh in place of the tailgate is more fuel efficient than driving with your tailgate up. The Test: Jamie and Adam test all of these pickup myths by measuring the fuel efficiency of each method while driving on a straight road at 55 mph. The Result: Driving with the tailgate down increases the drag and thus is less fuel efficient than driving with the tailgate up. The closed tailgate creates a vortex in the bed of the truck that allows for smoother flow of air than when the tailgate is down and the vortex is dispersed. This myth is busted. However, upon their revisit to the myth in a later episode, the mesh proves to be the most fuel-efficient method, while no tailgate, the hard-cover top and the tailgate up prove to be about the same fuel efficient.

https://www.scangauge.com/tips-trick...d-gas-mileage/ - no statistical difference

https://www.consumerreports.org/cro/...nomy/index.htm - Tonneau cover, or lowering tailgate, HURTS fuel economy.

 

This has been debated since the 1970's during the great oil embargo and gas shortage. At the time virtually every truck magazine as well as Outdoor Life, Field & Stream and others tested the theory and wrote articles on it. I've seen at least a dozen such tests over the years including twice on Myth Busters. Seen similar tests with caps and other covers.

In some tests they showed very minor gains in fuel mileage, some minor loss of fuel mileage (less than 1 mpg) with the tailgate down. I've seen at least one test where taking the tailgate completely off did result in roughly 1 mpg gain. The tests with caps and covers that I've seen have been more inconclusive. Some show about 1mpg better, some about 1 mpg worse.

The air hitting your tailgate doesn't prove you're getting worse fuel mileage. At best any gains in fuel mileage by leaving the tailgate down won't come close to paying for the damage you'd do to your tailgate if you back into something with it down. Nor would the fuel savings of a cap or cover pay for the cap. If you want a cap, or cover on the truck then buy one. I have caps on all of my trucks, but I don't kid myself into thinking they help fuel mileage.

The only cost effective modification you can do to your truck to improve fuel mileage is to ensure proper tire inflation. Under inflated tires will reduce fuel mileage 1-2 mpg. Learning to drive efficiently can make 1-2 mpg difference too. Neither of those cost anything.

 

Your test was not scientific - it didn't show anything useful. If you want to understand why, study fluid dynamics in college. If you don't have that much time or money, just trust the people who work for Ford - they did.

 

If anyone here is concerned with gas mileage you probably shouldn't have bought a pickup truck and surely not an 87-96 model

(Sorry I'm just being a wiseass)

 

I took fluid dynamics, Hydraulic engineering, and thermodynamics in college (Civil Engineering) and i can tell you that i didn't learn anything about obtaining better fuel economy with a truck tailgate down, lol!!!!!

 

Yeah, but CEs aren't real engineers! They just play in the dirt. :P

 

I've seen all the tv shows and read a lot about the tailgate up or down didn't really do anything. 'I don't care about gas mileage'. I was just wondering if the test were done on old trucks like ours, would they be any difference in gas mileage or the air hitting the tailgate. In 1965 my cousin's Dad bought a new (1965) Chevy farm truck with a 6 cylinder. I was 12 years old and he was 16. We would go riding around because he had just got his drivers license. I asked him why he drove around with the tailgate down all the time. He said, "I'll show you". We went on a road with around a 4 mile straightaway. The truck topped out around 75 MPH with the tailgate up. We went back on the same road and same direction. With the tailgate down it topped out around 80 MPH.

I think our old trucks cabs are lower and the air hits the tailgate more than the new truck with the higher cabs.

 

How about the difference between a long bed and a short bed? I drive a long bed and never think about it.

 

I did a scientific test back in the 90's.

I had a tonneau cover that would trap air because the design back then wasn't as good. I learned how much air was behind held up because of the stupid tailgate up.
Lowering the tailgate had zero effect. LOL

Do what makes you happy. If you feel saving gas can be had by lowering the gate and you're okay with it always bouncing around and/or getting rock chips. By all means.

At the end of the day, you can speed up from a stop sign once per day and negate your total economy more than a tailgate will.

Alternatively, removal of the gate is best as it no longer acts as a wind dam and you save weight. Paired with never filling above 1/2 day and it's a win win.