Ford's humiliation: The T-Bird is dead.

Reviews of cars, trucks, and other autos.
April 23 2003 3:18 AM

Ford's Humiliation

Is "Retrofuturism" a thing of the past?

(Continued from Page 1)

Let me explain!

Sometime in the early 1980s, I asked my friend Paul why he drove a crass Chevy Camaro. He said he liked the "balance" of a rear-wheel drive car. I nodded but secretly sneered at him. Everyone knew that front-wheel drive cars were the efficient, sophisticated wave of the future. Audis were front-wheel drive. Saabs were front-drive. GM, Ford, and Chrysler were  about to embark on a massive shift to front-drive, resulting in the current Detroit product lineup, in which even the venerable Caddy DeVille is a front-drive car.

The advantages of front-wheel drive (FWD) seem self evident: By avoiding the need for a driveshaft connecting the engine in front with the rear wheels, front-drive cars save space. The entire drivetrain can be packed into a neat compartment in the front, leaving the rest of the car's volume for passengers and cargo. Plus, front-drive cars have better traction in slippery conditions (in part because the weight of the engine is on top of the wheels that are providing the power).

I should have realized the grim truth decades ago when I borrowed a friend's Audi 100 –- the first front-drive car I'd ever driven -- and took it out on Sunset Boulevard. In one of the curves leaving Beverly Hills, near the pink house that used to be owned by Jayne Mansfield, I mashed the throttle, expecting the satisfying "lock in" effect I got in my old rear-drive Volvo – the nose turning in, the car seeming to stop slipping, tightening its grip on the road even as it went around the corner faster. But that's not what happened. What happened is the front tires went all gooey and the car started to head for the living room of a nearby mansion. Only panicked braking calmed things down.

Naturally, my brain did what the human brain tends to do with a bit of aberrant data: I ignored it. All during the '80s and '90s the car magazines assured me, seemingly continually, that in sophisticated front-drive designs you couldn't even tell which set of tires was providing the power. Weren't front-drive Hondas the hippest cars around? Wasn't even Volvo switching, belatedly, to front drive? I also blamed the victim! I must just be a lousy or unsophisticated driver, I figured.

Then, a bit over a year ago, I conducted an abortive test drive of five convertibles. The idea was to sample cars that had at least a semblance of a rear seat. The entrants were Ford Mustang, Chevy Camaro, VW Cabriolet, Chrysler Sebring, and Toyota Solara. And that was the order of finishing (though the test was interrupted by 9/11 before I could drive a final production version of the Toyota). None of the cars was very good – you give up a lot  in chassis stability when you chop off the roof, I discovered. But the old, junky, rear-drive Ford and Chevy pony cars were by far the most enjoyable – they rattled and guzzled, but at least they were a blast to drive around corners. The other three cars, all front-drive, were simply pleasant forms of transportation.  

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Why are rear-drive cars more fun?  Every enthusiast may know the answer, but I didn't. So I called up a helpful GM suspension expert, Vehicle Chief Engineer Ed Zellner. There are, I learned, five basic reasons:

1) "Balance":  The car rides on four patches of rubber, each about as big as your hand. An ideal car would distribute its weight evenly, so each tire had to bear the same load, and none would give way earlier than all the others.  The ideal weight distribution, then, would be split about 50/50 between front and rear (actually, 48/52 to help with forward pitch during braking). "A rear-drive car can typically approach that," says Zellner. Engineers can move the front wheels forward, so that the engine – which doesn't have to be connected to those wheels -- sits behind the front axle. Meanwhile, the driveshaft and rear differential (necessary to send power to the rear tires) add weight in the rear. Front-drive cars, which must connect the engine and transmission to the front axle, typically have their engines mounted way forward and can't do much better than a 60/40 front/rear weight distribution.

2) Center of Gravity: This is the point the car wants to "rotate around" in a turn. On a rear-drive car, it's "about where the driver sits," says Zellner. In a turn, in other words, the car seems to be rotating around you – you're at the center. It's a natural pleasant effect, suggesting you're in control, the way you're in control when you're walking or running around a corner and your weight is centered inside you. (Analogy No. 2: It's like wearing stereo headphones and having the sound centered between your ears!) A front-drive car, in contrast, with its massive front weight bias, wants to rotate around a point in front of the driver. So in a corner, the driver isn't just rotating around his spine. He's moving sideways, as if he were a tether ball on the end of a rope, or Linus being dragged when Snoopy gets hold of his blanket. Not such a pleasant feeling, or a feeling that gives you a sense of natural control.

3) "Torque Steer": One of the most annoying habits of many powerful front-drive cars is that they don't go straight when you step on the accelerator! Instead, they pull to one side, requiring you to steer in the other direction to compensate, like on a damn boat. This "torque steer" usually happens because the drive shafts that connect the engine to the front wheels aren't the same length. Under power, the shafts wind up like springs. The longer shaft -- typically on the right -- winds up a bit more, while the shorter left shaft winds up less and transmits its power to the ground more quickly, which has the effect of pulling the car to the left. (This winding-up phenomenon occurs the moment you step on the pedal. After that, the wind-up relaxes, but "torque steer" can still be produced by the angles of the joints in the drive axles as the whole drivetrain twists on its rubber mounts.)

Veer madness?
Veer madness?

Engineers try various strategies to control this veering tendency, but even designing shafts of equal length (as in all Cadillacs) doesn't completely solve the problem because the engine still twists a bit in its mounts and alters the angles of the drive shafts. True, some manufacturers -- Audi, for example -- are said to do a particularly good job of repressing torque steer . But even a top-rank company such as Nissan has problems -- its otherwise appealing new front-drive Maxima is said to be plagued by big-time, uninhibited torque steer. Rear-drive cars, meanwhile, don't really have a torque-steer problem that needs repressing. Their power goes to the rear through one driveshaft to a center differential that can a) have equal-length shafts coming out from it and b) be more firmly mounted.

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