Who is more engine considerate: an early-shifter or a late-shifter?

Dear Car Talk

Dear Car Talk | Feb 01, 1998

Dear Tom and Ray:

It ain't genetic, so what is it? My daughter and I both have manual transmission
cars, but she is a confirmed "late shifter," and I am an equally confirmed
"early shifter." She goes into fourth gear at about 2,500 rpm, while I go into
fourth at about 1,500.
I taught her to drive about 30 years ago. She married a guy who is a late
shifter. So please tell me who is being more engine-considerate, and how you
account for this difference between us. -- Jason

RAY: Well, Jason, just be glad that she isn't like my brother. He's completely

TOM: I don't think either one of you is being inconsiderate to your engine,
Jason. The truth is, by shifting earlier, all you're doing is trading off some
acceleration for some fuel economy. Based on your description, neither one of
you could be described as a bona fide "motor wrecker."

RAY: Shifting up at 2,500 rpm, as your daughter does, is well within the
acceptable range of engine speeds. In fact, most manufacturers probably would
recommend shifting somewhere between 2,000 and 3,500 rpm. So we can't criticize
her at all.

TOM: If she were constantly shifing at 4,500 rpm, then she'd be subjecting the
engine and clutch to some excessive wear and tear. But she's nowhere close to

RAY: And your earlier shifting is mostly fine, too, and even saves you some
gasoline. But believe it or not, you're actually in more danger of being
"engine-inconsiderate" than she is. While shifting at 1,500 is fine on flat
roads under moderate acceleration, you have to be careful not to shift too
early, or you'll "lug the engine."

TOM: That doesn't mean you get out and drag the engine around with a rope.
Lugging is when you force the car to try to accelerate in too high a gear (at
too low an rpm). That causes the engine to strain and overheat. The telltale
sign of lugging is when the engine bucks, pings or knocks.

RAY: If you ever notice any of those symptoms, then you need to take a driving
lesson from your daughter and learn to shift a little later, Jason.

TOM: And how do we explain you being an early shifter and your daughter being a
late shifter? The answer is simple, Jason. It IS a genetic trait. But the
genetics lab at MIT recently determined that it skips a generation. Which means
that your father was probably a helluva lead foot!

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