Does a convertible get better gas mileage when the top is up?

General Discussion
21

“Does a convertible get better gas mileage when the top is up?”

Yes, no doubt about it…

22

"Yes, no doubt about it… "
I agree in general, but; I’m sure there is some convertible out there that might be an exception. The over all aerodynamics could in some car be so altered by a top that was so poorly designed compared to it’s convertible state, it just might be that exception. Perhaps some Ferrari from an earlier f1 design made road ready; just guessing at this point…

23

The Shelby Cobra’s maximum speed was severely limited without a top as best I recall. There was a significant increase in top speed with a fitted top. I must infer from that, an increase in fuel mileage would be as significant at high speed.

24

Thinking about it, no one has asked the main question:
“Does it matter?”

25

As a green person, it would matter to me.

26

The only thing close to a convertible I’ve ever owned was an old Corvette with a removeable hardtop.
This car saw a lot of open road use and if there was any difference in fuel economy with the top on or off it was so slight that I could not detect the difference.

27

I agree with Bscar: “Does it matter?”

At 5 mph, you’ll get the same mileage - top up or down.
At 100 mph, you can assume you’ll get worse mileage with top down.

The crossover point for any car is dependent on more variables than can be analyzed here. And as others have noted, in many cases where it does make a difference, the difference will be difficult to detect or measure.

28

I do recall a Mythbusters show where they tested MPG in a pickup truck, tailgate up vs. tailgate down, the theory being that gate down decreased resistance. Tailgate up got better economy, though.

29

Robert Gift: “As a green person, it would matter to me.”

Then you are not a good candidate to drive a convertible, for two reasons:

  1. Most importantly, convertibles are for people who have a carefree attitude, so if you have to ask…

  2. The consensus is, generally, you get better fuel economy with the top up, so if your greenness wouldn’t let you put the top down, you might as well drive a normal car.

30

We’ve had a few lengthy threads on the tailgate question. I’ve tested it personally, and in my case I found no difference. The test wasn’t "controlled’, but it was 1000+ mostly highway miles a week for weeks at a time with the gate up & then down. I had an insanely long commute back then…103 miles each way. It was enough to convince me that in my pickup it made no difference.

31

Whitey says: "1. Most importantly, convertibles are for people who have a carefree attitude, so if you have to ask… 2. The consensus is, generally, you get better fuel economy with the top up, so if your greenness wouldn’t let you put the top down, you might as well drive a normal car."
You are precisely correct. I would forego the top down unless at lower speeds where it would not matter.

32

So, I am going to run the world out of gas because I will go on the interstate in my T’bird with the top down! What a bad boy I am. This thread is a joke based on the dumbest question ever.

33

Agreed.

“I’m going to get a convertible, but since I’m ‘green,’ I’m only going to drive it 30 MPH when the top is down.”

Robert, seriously, don’t get a convertible. It would be a waste to own one and not drive it 70 MPH with the top down.

34

Whitey,ou are correct. My attitudefeats the whole reason for driving a convertible. WithexpensivExpedition, I could never afford one, anyvay.

35

Naw, I can’t agree. A convertible with the top down on a nice spring or summer day, or especially a nice fall evening, is still great. To have the sun or to have the spring or fall smells swirling all around you…you don’t need speed to enjoy a convertible. As a matter of fact i’d argue that most of them are best enjoyed at speeds under 50 mph. On a nice country road, or at the beach smelling the salt air.

36

"As green person, it would matter to me"
As a green person, why drive an Expedition ?

37

Only experience I have driving a convertible was a test drive of a Miata a couple years ago. At freeway speeds(70mph), my head felt like it was taking a beating with the top down.

38

Another part of the answer is weight. Generally convertibles are heavier than hardtops. Weight always means reduced mileage.

39
The dimples removed weight from the extra they added on it, so yeah, shedding several pounds from the car's weight would have an effect on the MPG. Remove ALL the clay and see how many MPG they got
They did that initially. They found that the MPG was the same as with the clay on. Their reasoning was that although the added weight would have decreased mileage during the initial acceleration, once up to speed the added weight's effect on mileage was negligible.
40

Whitey, Kermit is ok, maybe bad, how about Van Morrison for a song instead. If yo spend the money to get a convertable are you really going to worry about a few mpg ?