Leave the Tailgate Up for Better Gas Mileage

My husband and I are watching Mythbusters on Discovery ... they're testing the myth of the tailgate down vs. tailgate up as it relates to gas mileage for trucks. The myth is that you'll get better gas mileage with the gate down (the thinking is that it makes the truck more streamlined). They tested it two ways and found that the myth is false.

Leaving the tailgate down actually creates major drag. With the gate up, air gets trapped in a circulate motion bubble in the bed and actually creates a streamlined flow of air. When the gate is down, the bubble is lost and the air falls right on the gate, creating major drag. Their tests showed that you could get 30 more miles on a tank of gas with the gate up.

Tailgate Up or Down Revisited: Mesh tailgate, hardcover, tailgate removal

See: Tailgate Up or Down

For the original myth they did a driving test and a water vortex test, both of which showed that you save more gas with the tailgate up. Their viewers suggested that they test three new conditions:

* Hardroof cover over pickup bed
* Mesh tailgate
* Remove the entire tailgate

They had a much simpler test setup this time. They had an electronic flowmeter hooked into fuel line of Jamie's pickup. Adam: "For anyone out there that wants to e-mail telling me that we screwed up this test, we have already calibrated this thing, to this car. So it's going to be perfect!" They drove the pickup truck up and down the stretch of 101 around Candlestick and the Cow Palace.

* Tailgate down: 5.2 gallons/hr @ 55mph. 1.2 gallons/hr @ 25.
* Tailgate up: 5.0 gallons/hr @ 55mph. No reading for 25mph given, but tailgate up was once again confirmed as more efficient.
* Hardcover over pickup bed: 5.0 gallons/hr @ 55mph. 1.2 gallons/hr @25mph
* Tailgate mesh: 5% more efficient
* Tailgate removed: about the same as tailgate up and hardcover

Mesh was most efficient by 5%

still busted