Sometimes, Steering With Great Feel Is the Last Thing You Want
As I learned by crashing a Shelby Mustang GT350 with excellent steering.
ACCORDING TO OCD.XLS, the Excel spreadsheet I use to keep record of every car I’ve driven, I logged 190,214 miles in 2015 different test cars before I finally managed to crash one. I immediately called Ford to take full responsibility for backing the pretty orange Shelby Mustang GT350 through a tire wall. I apologized, like any good man should. Then, like even the best men do, I started looking for someone else to blame.
As I was sliding backward off the track, all I could think was that I couldn’t turn the wheel quickly enough to correct the slide. Which is funny, because I had just finished praising the GT350 for its heroically communicative electric power-assisted steering (EPAS). I was mildly relieved when I later learned that multiple colleagues have spun GT350s trying to hold drifts. So I added a few notes to OCD.xls, including “Never powerslide a Shelby, ever,” and “Have more sympathy for drivers wadding up Mustangs on their way out of Cars and Coffee events. Maybe it’s not entirely their fault.”
That got me thinking. I’ve done literally thousands of drifts in BMWs, for example, and never lost control of a car like I lost that Shelby. I talked to BMW’s head of chassis tuning about this, and it turns out, he’s found that some cars don’t measure up to several of his company’s maneuverability tests.
One test in particular simulates the worst-case scenario for a power-steering system: The car is parked on a concrete surface wearing its highest-friction tires (typically the widest-available summer performance tire) and loaded to its maximum-permissible front-axle weight. With the brakes applied, drivers of varying strength and stature must each be able to turn the wheel quickly—something like 600 degrees per second. In an M2, for instance, that means getting from lock to lock in just more than a second. This is important for parking but also a boon to safety when, say, making a three-point turn on a road with restricted visibility.
Spin the steering wheel on any stationary Mustang, and you’ll find that the assist motor doesn’t have the grunt to scrub the tires against the pavement quickly. Or, one assumes, to counteract the tremendous forces acting on the front end of a sticky-tired Shelby when some yahoo is doing a full-opposite-lock powerslide on a closed track. (I have now successfully blamed someone else for my crash. I am a hero in my own mind.)
Whether it’s a four-cylinder on skinny all-season tires or a monster Shelby, all Mustangs use the same steering rack—and its EPAS motor is visibly small. Ironically, this may be one of the reasons for the GT350’s brilliant steering feel. One of the primary drawbacks of EPAS is that the motor acts like a damper for road feel. Every time the front wheels change direction even the slightest amount, the motor has to spin up and then slow back down. The more powerful the motor, the bigger and heavier its rotating parts, and the more it dampens the forces coming back to your hands.
This is one reason that BMW, with its powerful EPAS motors, has fallen from steering-feel grace more than any other carmaker in the transition from hydraulically to electrically assisted power steering. I’m practically homicidal over the numb steering in most modern BMWs, but even I have to wonder whether the loss in feel is worth the safety benefit. As I was skidding backward toward the wall in the Mustang, I might have said yes.
But at any time during the previous 190,214 miles, I would’ve argued that Ford’s trade-off was worthwhile. If we never compromised on safety, we wouldn’t be driving at all—the computers would be doing most of the work, with layers of human oversight and mechanical redundancy. In fact, that very world exists. It’s called commercial flying, and it’s the safest way to travel. It’s also boring as hell.
Not boring: a Mustang mowing down a couple of signposts with a crowd of hooting onlookers. I’ll take my chances. I just wish someone had a camera on me when I crashed that Shelby. It would have made a great YouTube video.
Source from https://www.roadandtrack.com/car-cul...paign=17370813
