Friday, January 6, 2017
Driving on Ice: Advice from Walter Rohrl
Text first published in the Porsche customer magazine Christophorus, No. 379
Text: Wolfgang Schäffer // Photos: Stefan Bogner & Anatol Kotte
Walter Röhrl’s answer is short and sweet. “Like always,” he says when asked about the best way to drive on snow- covered surfaces. The hint of a smile, however, suggests that his response applies only to people who share his level of skill. When Röhrl (69) says it makes no difference whether he’s driving on dry asphalt, dusty dirt roads, or icy streets, you believe him immediately. He intuitively knows the best way to handle a car.
But what skills do we really need in order to not lose our grip—or face—on slippery surfaces? For those of us who aren’t world-champion rally drivers, Röhrl has a few tips on how to handle cars safely in winter wonderlands of snow and ice. “Be even more attuned to the car than usual, and concentrate completely on what you’re doing,” he says. All of your senses have to be focused on what the car is telling you. But that alone is not enough. “Winter conditions reduce the amount of friction on the road, which means a dramatic drop in grip. So you have to slow down. Otherwise, you’ll have problems when you brake or hit the next curve.” Even though all-wheel-drive systems like that in the Macan offer a lot of advantages when accelerating on slippery surfaces, the reverse—that is, when decelerating—does not apply. “We shouldn’t forget that mass generally keeps moving straight ahead. And it doesn’t matter whether the engine transfers its power to one or both axles. That doesn’t affect the braking power.”
But in general, Röhrl sees all-wheel drive as a major benefit and a plus for safety. “If the engine power is distributed across all four wheels, the car can hold its course better when accelerating,” he notes. In other words, dividing the power among four tires reduces the tendency of individual tires to lose their grip as the car speeds up, which could cause it to swerve. “But just because cars like the Macan can master these situations doesn’t mean you should try to show off,” he adds. A virtuoso at the wheel himself, Röhrl urgently warns drivers about a grave error that can also be seen at rallies: entering curves too fast will get you nowhere. “It’s not a good idea to take momentum into a curve on slick roads, not even with all-wheel drive,” he says. “But good traction will allow you to step on the gas sooner and accelerate out of the curve. After all, there’s no shortage of power.”Röhrl, a native of the German city of Regensburg who is also a passionate skier and cyclist, has a very general piece of advice for such situations: “Keep steering maneuvers to a minimum. And don’t tense up.” All steering actions beyond what is absolutely necessary come at a cost in terms of time and safety—except for strong movements at the wheel that make driver-assistance systems kick in sooner. “That all just creates anxiety,” he says. Röhrl, an admitted perfectionist and advocate of minimalist driving styles, raises his hands in front of his chest and turns an imaginary steering wheel to the left and right with two fingers and a thumb on each side. We might say he’s sitting at the wheel even when he’s just talking about it. The Macan’s cutting-edge driver assistance systems ensure safety
If you enter a curve too fast, it’s nearly impossible to control the car—especially on roads covered with snow or ice. “When I say slow down, it’s not because I’m an old man,” he says. The Macan’s cutting-edge driver assistance systems may offer more safety than ever before, but they’re powerless in the face of one thing: a curve that is entered too quickly. “People aren’t immune to the laws of physics,” he says, “and neither are cars.”
But what should you do if, despite ample caution, you find yourself approaching a curve too fast? The first thing to do, of course, is to decelerate as much as possible by hitting the brakes hard, so that the anti-lock system sets in as quickly and efficiently as possible and reduces the speed. If need be, you also want the anti-lock system to work in the curve, even if that means having to turn in more sharply.
Given his experience as a professional rally driver, Röhrl naturally has an alternative approach, although it requires strong nerves on snow-covered roads, not to mention extensive training. “If there’s no other recourse, then lift your foot from the brake right before the curve and turn in—but not too much—and be very attuned to the car. Wait for the car to catch up, reducing the angle if need be to prevent oversteering, and that might enable you to keep the car on the road.” Regardless of skill level, one requirement applies to everyone: winter tires are a must. “Steering and driving maneuvers work only if the tires have enough grip on the road. So you absolutely have to have the right tread and rubber blend for cold temperatures.” Regardless of whether a car has front-, rear-, or all-wheel drive, it needs winter tires to transfer its power to the road and to brake in the most effective way possible—and this applies to everyone, including a two-time rally world champion like Röhrl.
“Nobody should think that all-wheel drive will make you safe in winter with summer tires,” he says. This fallacy can have grave consequences because, compared to how they perform on dry asphalt, summer tires transfer only an average of about one-tenth of that power to snow-covered roads. Crucially, this also means the driver has only about 10 percent of the braking powerAs far as the Macan is concerned, Röhrl thinks it offers very good performance, independent of the actual engine power. He especially enjoys driving it on snow. “In the many test-drives I’ve done with this Porsche, it has shown very close affinities to rally cars, particularly under winter conditions,” he says. “Turn in, brake straight into the curve, let the car gently catch up, and power out onto the straight. We didn’t test that on public roads, by the way.” Röhrl wouldn’t be Röhrl—a role model for responsible driving—if he didn’t add, “That’s completely against the rules on normal roads.” He also cautions that drivers should get to know and learn to control their cars’ steering behavior, especially under winter conditions—because, as the saying goes, “practice makes perfect.”