Nick Miller
Active Member
Would removing the tailgate and spare tire increase MPG? Has anyone tried this?
better MPG?
- Thread starter Nick Miller
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Kevin Palmer
Well-Known Member
Only because of less weight, not because of aerodynamics.
In fact, mythbusters found that with the gate up, you actually improve the mileage as the air flow circles and creates an area that decrease atmospheric pressure, thus, the vehicle is over-all lighter.
In fact, mythbusters found that with the gate up, you actually improve the mileage as the air flow circles and creates an area that decrease atmospheric pressure, thus, the vehicle is over-all lighter.
TomT
Well-Known Member
Go on a diet and you can achieve the same gain in mpg. 
Kevin Palmer
Well-Known Member
Here is a cut and paste from the specific episode...
Tailgate: Up or down?
Myth: Driving your pickup with the tailgate down gives you better fuel efficiency than with the tailgate up.
Update: Tailgate Up or Down Revisited
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:
They have to maintain the speed limit
All acceleration must be done by cruise control
No drafting
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 behind 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
Here is more on how the test was actually done...
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
Tailgate: Up or down?
Myth: Driving your pickup with the tailgate down gives you better fuel efficiency than with the tailgate up.
Update: Tailgate Up or Down Revisited
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:
They have to maintain the speed limit
All acceleration must be done by cruise control
No drafting
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 behind 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
Here is more on how the test was actually done...
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
Kevin Palmer
Well-Known Member
Sorry, double post...
Last edited by a moderator:
EddieS'04
In Memoriam 1950-2022
MIT, performed the same test 2 yrs ago. They got the same results as myth-busters.
Matthew W
Active Member
Removed my spare tire (truck's that is ... mine is permanent , tonneau cover, bed extender, bed mat and a few other items out of the bed (roadside kit, tow rope, yadda yadda...) and noticed a gain ... about .5-1.0 mpg ... added to changing my driving habits, gained about 1.5-2 mpg total.
note - spare is 255/70/16, other 4 are 285/75/16's, so spare is mostly useless ... unless short trip to tire place
, tonneau cover, bed extender, bed mat and a few other items out of the bed (roadside kit, tow rope, yadda yadda...) and noticed a gain ... about .5-1.0 mpg ... added to changing my driving habits, gained about 1.5-2 mpg total. note - spare is 255/70/16, other 4 are 285/75/16's, so spare is mostly useless ... unless short trip to tire place
Last edited by a moderator:
