Lately I’ve been driving around 300 miles per day, mostly highway, for work. I have an '01 Ram that gets around 15mpg. Is putting the tailgate down doing anything at all to improve my wind resistance, thereby improving my mileage? A few years ago, a caller asked this on NPR’s Car Talk. Tom and Ray said no, but they didn’t explain and quickly moved on. At $3 per gallon and around $56 per day, even a little improvement would be worth it.
Anyone?
One site that says it’s marginal
Most things I’ve read on this subject say the same.
I read a newspaper column by the Car Talk guys about this. They had talked to some truck designers. Bottom line: The truck was designed to have the best aerodynamics with the tailgate up. Lowering or removing it is a lose.
There’s an “air pocket” over the truck bed that smooths out the flow over the truck and without the tailgate, that goes away.
Believe it or not, engineers working for the automakers know a lot more about the details of airflow than most people.
Can’t you just adjust your expenses claim?
I’ve heard that, as others have posted, the difference is marginal or nonexistent. But once, on a trip from Memphis to Des Moines, I drove about halfway with the gate up, then put it down. I kept close tabs on my mileage the whole time. The results:
Tailgate up: 24 mpg
Tailgate down: 30 mpg
Bear in mind that I drive a 1989 Isuzu pickup (no laughing, please); engineers may design trucks to account for airflow and such in newer trucks.
It’s anecdotal, but at least it’s a true anecdote.
This is what I heard too. Also at highway speeds it lessens the down force on the rear wheels making handleing worse. But as the saying goes YMMV so try it for yourself.
Use a bed cover.
I heard this on Car Talk years ago. ISTR reading an article about it wither here on The Straight Dope or over at Snopes that agrees with them.
‘either’.
I’ve been told the same thing in fluid mechanics. From the perspective of the driver’s side of the truck, there is a clockwise-spinning pocket of air formed when the truck is moving at highway speeds with the tailgate up. The surrounding air flows over this pocket, rather than down into the bed and against the tailgate.
So this would make a bed cover unnecessary, from an aerodynamic point of view?
And the Air Flow Tailgate may be wrong when they assert
Well, I did read an article on this – but it was from the Car Talk website. No wonder it matched what I’d heard!
Considering Dodge hasn’t been able to put a reliable transmission in their trucks despite a decade of complaints, I didn’t have a ton of faith in their aero-studies.
One obvious thing to consider would be driving something other than a pickup truck (the aerodynamics of which are irretrievably bad). It’s easy to find cars that get twice the gas mileage of typical pickups. Towing a utility trailer (which would carry a load similar to the pickup’s), that would drop to, say, 160% of the pickup’s.