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Car Talk Columns

February 1998


Dear Tom and Ray:

It ain't genetic, so what is it? My daughter and I both have manual transmission [bluecar2.gif] 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 "shift-less"!

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 that.

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!


Don't get stuck with a lemon. Be an informed shopper. Read Tom and Ray's guide "How to Buy a Great Used Car: Secrets Only Your Mechanic Knows." To order, send (check or money order) to Ruin, P.O. Box 536475, Orlando, FL 32853-6475. You can also order online.


© 1998 by Tom and Ray Magliozzi and Doug Berman Distributed by King Features Syndicate, Inc.

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