Removing your tailgate - Better fuel economy or not?

Answer 1

Tailgate: Up or down?

Myth: Driving your pickup with the tailgate down gives you better fuel efficiency than with the tailgate up.
Test Setup

Adam and Jamie were each given identical, new model pickup trucks. They both had equal mileage, same tire pressure, and 30 gallons of gas. Jamie drove with the tailgate up and Adam the tailgate down.

The rules:

1. They have to maintain the speed limit
2. All acceleration must be done by cruise control
3. No drafting
4. Windows up, A/C must be exactly the same in both cars

The Test

After 300 miles there didn't appear to be much difference in the gas consumed, but after 500 miles Adam (tailgate down) ran out of gas. Jamie made it another 30 miles before he ran out of gas. This result was the exact opposite of the myth.
Water tunnel visualization

According to the experts, a circular pillow of air forms behidn the cab of the truck when the tailgate is up. This "separated bubble"/"locked vortex flow" keep the faster moving air from contacting the truck, and thus reduces drag. With the tailgate down, the bubble breaks down and is no longer able to keep the fast moving air out, increasing drag.

In their scale model with the water tunnel, they were able to see that the increased drag. With the tailgate down, the particles in the water were dropping down and hitting the tailgate.

mythbusted

November 16, 2005 | Permalink

Answer 2

Believe it or not you actually do not get that much greater mileage, the TV show Mythbusters did an experiment on this. It has to do with the air pocket that is formed between the tailgate and back window. With the tailgate up the bubble pushes the air over and makes the truck more streamlined. Without the gate the air moves faster resulting in more drag. Episode 43 "Returning to shore, Adam and Jamie hit the road in a fuel efficiency special. They seek to answer the age-old question: Does driving with your pickup's tailgate down save gas and, hence, money? "

Answer 3

Mythbusters actually proved that it was better fuel economy to keep the tailgate up.
Simply, it has to do with air flow. A trapped "balloon" of air circulates between the cab and the bed. When the truck accelerates, the air flow hitting the front of the truck actually flows over the cab and this "balloon." When the tailgate is down, the "balloon" no longer exists and the air flow then gets trapped just behind the cab creating drag. The model used was a wind tunnel with smoke to better illustrate the flow patterns in both instances.

Answer 4

There is, but they wont help improve mpg much. The spare tire is a biggie. You might be able to get a few mpgs removing that. if you want to increase mpg try installing some performance parts. Here is a list of several that will improve fuel economy. 1. Fitch catalyst fuel filter 2. K&N air filter and oil filter 3. Bosch platinum spark plugs 4. New chip 5. New Pcv valve 6. MPG PLUS Premium Ignition Wires

Answer 5

Not. The wind doesn't hit the tailgate when it's up. It just goes over the top. Lowering the tailgate actually creates turbulence and lowers your mileage.

Answer 6

No. Even driving with it down won't save gas. A pocket of air forms with it up and incoming air travels over this and out past the tailgate. With it down, the incoming air hits the bed and produces drag.

Answer 7

I remember some tests made, several years ago. I cant recall the source.

Upshot was that it made little difference. The truck bed, directly behind the cab was in the middle of so much turblence, that the gate's presence had little effect.

I know that after market retailers sell those cloth barriers to replace the gate, but those are mostly for fast truck racer wannabes.

If there is any fuel economy from removing the gate, it will be from a weight savings.

Answer 8

It does sounds reasonable as there is a freer flow of air if the tailgate is removed. A lot of people do this. But also remember a lot depends on what kind of driver is behind the wheel.

Answer 9

I used to think it really helped, but I recently read an article in a Major Auto magazine that said they did a through study at various legal road speeds and slightly higher and did not see any difference. Probably most important is to have a slightly elevated tire pressure and check same at least once a month as well as a clean air filter; replace at least once a year, as well as a good annual tuneup.

Answer 10

Bottom line; yes,because of the pure physics. How much (fuel economy) would depend on the variables.