Why aren't cars using better gear ratios for better gas mileage...or are they?

Dear Car Talk

Dear Car Talk | Dec 01, 1996

Dear Tom and Ray:

Since everyone is complaining about cars getting poorer gas mileage with
the recent raising of speed limits, why don't manufacturers start using
better gear ratios in cars, so the engines are turning slower while the
cars go faster? -- Frank

RAY: They are, Frank. And actually, they have been for some time.

TOM: Engines used to turn at 3,000 rpm at 60 mph. Now, most cars with four-
speed automatic transmissions turn well below that. Some, like the Buick
Park Avenue I was driving recently, turn at about 1,700 rpm at 60 mph!
That's about half the speed engines used to turn.

RAY: And you'll see much more of that, especially with more and more five-
speed automatics coming out now. Mercedes, BMW and Ford all have five-speed
automatics in some of their '97 cars, which give you the higher ratios and
better gas mileage in high gears, without sacrificing the "oomph" (that's
technical jargon) in the lower gears.

TOM: In other words, they're on it, Frank. At ease.

Get the Car Talk Newsletter

Got a question about your car?

Ask Someone Who Owns One