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µ-Low, Sweet Chariot
Driving a sports car between “go” and “no go”— the
ultimate driver safety training with Walter Röhrl.
By Jo Clahsen; Photos by Thomas Hörner
large billboard displays some advice utes’ walk from the µ-low shower, a series
A from the Austrian Traffic Safety Board:
“Drive like a pro. Cool and composed, us-
of moderately to extremely difficult driving
assignments awaits the participants in the
ing your head.” A nice idea. It is only a short driver safety course. But before Röhrl al-
distance from the billboard to the driver- lows the men and women to take the wheel
safety center in Saalfelden, where Porsche of their Porsche, there is more theory to be
representative Walter Röhrl puts this theory learned.
into practice. “Doing it in practice is hard enough,”
The course begins with a striking illus- Röhrl says with a grin. “You should at least
tration: A showerhead slowly slips down the try to have a grasp of the theory and
metal shower bar, together with its mount, physics of driving.” He then briefly but vivid-
on a film of water. Engineers call this phys- ly explains the factors at work in the trans-
ical state, which occurs when there is no mission of forces. He points out that four
adhesive friction to impede movement, surfaces no larger than the palm of your
“µ-low” (pronounced “moo-low”). A few min- hand have to transmit all these forces to
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Waterworks: Voice of experience:
The fountains create so- Walter Röhrl knows
called “soft” obstacles all the tricks of
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driving on the edge
22 Christophorus 298 298 Christophorus 23
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the road. That is why “there is hardly any
part of your car more important than the
tires.” In order to allow them to perform
their task in optimal fashion, it is crucial that
“speed be at its slowest when entering a
curve, so that the tires only have to trans-
mit the steering forces.” Using the example
of a circle of friction, which demonstrates
the bundled centrifugal and centripetal
forces in one diagram, the former World
Rally champion shows how thin the line can
be between “go” and “no go.”
So far, so theoretical, so good. If your
showerhead develops a µ-low problem, it’s
enough to take it off the hook and hold it in
your hand. At the sports car safety-training
course, everyone ought to get some hands-
on experience. But here, the µ-low problem
is a bit more complex. One side of the short
slalom has plenty of µ; the other half has
virtually no traction at all. That can be a
recipe for trouble. “But only if you are going
a tad too fast,” Röhrl assures the partici-
pants. If the course is dry, speeds of up to
80 km/h (50 mph) are possible without any have been set to help bring theory and the exercises is to experience these limits
cause for concern. Given µ-low and enough practice into harmony. As on the µ-low first-hand, to develop a feel for them and
water, however, the situation looks entirely track, which is continuously watered, any- to be able to recognize them in time in the
different. A mere thirty km/h (19 mph) is one trying to brake and simultaneously future. If the command comes over the two-
hard to handle, and at a speed of thirty- swerve to avoid obstacles here is going to way radio to turn off the PSM, the pirou-
two km/h (20 mph), the driver is essential- have to maintain a very high level of con- ettes that follow create an even more im-
ly powerless to prevent the car from spin- centration indeed. pressive acrobatic performance.
ning out. Röhrl describes the way a sports car be- Between the soup and the Austrian apri-
Making mistakes is thus a compulsory haves when performing such hazardous cot dumplings, Röhrl has little time to do
part of driver-safety training. After all, the maneuvers: “The car understeers when you what everyone else is there to do: eat. Dur-
goal of the course is not to reach high see the tree you are heading toward. That ing the lunch break, the affable and down-
speeds, but to see to it that “customer and means it is pushing over the front wheels to- to-earth Regensburg native is grilled on
car get to know each other so well that ward the obstacle. When you hear the tree, how this or that Porsche behaves on vari-
they are on a first-name basis.” That is how the car has oversteered.” It takes his lis- ous courses and which tires are best for
Volker Gempt, manager of the Porsche teners a minute to grasp the drama at the which driving conditions. His knowledge
Travel Club, defines the aim of the pro- end of the sentence. Fortunately, the ob- and experience are so vast that there
grams offered to Porsche customers on a stacles at the extreme-test site in Saal- seems to be no question he couldn’t an-
regular basis. The role of driving expert felden are not made of wood, but are “soft” swer right away. Whether on two wheels (a
Röhrl is then taken over by the profession- obstacles in the form of fountains of water. passionate cyclist, he recently biked over
al instructors from the Travel Club and the If a car oversteers and grazes the obstacle, 13,000 meters [43,000 feet] of altitude in
Austrian Automobile, Motorcycle and Tour- there is only a little splash. five days) or four, this amazing physical W HERE SHARPNESS H A S THE EDGE
ing Club, which runs the center. The velocity of the cars fluctuates rapid- specimen is open to any challenge. With in-
On the course spanning more than sev- ly between forty-five and fifty km/h (28–31 terest and patience, Röhrl provides infor- KYOTOP–the knife with the new
en hectares (seventeen acres), a few traps mph). The remaining test tracks, with ei- mation, shares anecdotes and gives advice high-tech blade made from top-
ther µ-low or mixed surfaces, also force packaged in dramatic, succinct sentences: quality Zirconium ceramics.
Slippery slope:
Driving is easier
the test drivers to moderate their driving “When you are driving at over 300 km/h See for yourself the knife that
with instructions techniques. (185 mph) and you hesitate for just one sec-
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stays sharper, longer! Now avail-
from Walter Röhrl The master of driving technique, Röhrl, ond before hitting the brakes, you have al-
sets approximate limits that, if maintained, ready lost ninety meters (295 feet) of stop-
able from well-stocked retailers.
should ensure safe passage through the ping distance. You’d better think fast.”
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problem zone. Yet none of the drivers can After the sweet dumplings, the partici-
avoid problems altogether, even if they pants are once again called upon to show
strictly obey Röhrl’s directives in precarious some quick thinking, along with some quick
situations. The car slips and slides and braking and some quick steering. They are
spins, even when the Porsche Stability Man- to approach a blind downhill stretch with a
agement system is turned on. The point of mixed pavement from behind an embank-
K YOCERA FINECERAMICS GmbH, Esslingen,
24 Christophorus 298 e.
T l : + 49 (0)7 11 9 39 34 21/9 39 34 34,
www.kyocera.de
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Information on driver safety training Walter Röhrl’s role as explained in the text will be
taken by professional instructors.
The Porsche Travel Club is offering driver safety Information is available at www.porsche.com
training in Saalfelden again in 2003. or by telephone at +49-711-911-8155 (fax -911-8158)
Dates: 30 May –1 June, and 15 –17 August. or per e-mail (travel.club@porsche.de).
ment at almost sixty km/h (35 mph). The the rear end, sends the cars spinning like ment in itself. And there on the side of the
task is to quickly begin applying the brakes tops on the slippery surface. Things get track is Röhrl proclaiming his encouraging
in measured doses while simultaneously better after each repetition, since now comments.
dodging the “soft” obstacles. A piece of everyone knows when the jolt is going to The longer that µ-low and the moisture
cake for the rally pro, but a daunting chal- come and can react as the champion sug- outwit the trainees, the more relaxed the at-
lenge for anyone else: “When I got to the gests: with fingers extended on the steer- mosphere becomes. Learning with a cham-
bottom, my adrenaline level was at an all- ing wheel in the three-and-nine-o’clock po- pion of Röhrl’s caliber is fun, even if what
time high,” moans a man from Berlin. Nev- sition and with calculated steering moves. you are learning could save someone’s life
ertheless, almost no one decides to skip He recommends “you feel with your hands some day.
this exercise. The participants’ desire to and your bottom when the car swerves and At the end, everyone gets a certificate of
prove their skills to themselves and the oth- then react quickly, but don’t overreact.” participation in the driver safety training.
ers is growing by the hour. Many of them try Easier said than done. The kick some- No one can rest on their laurels, though. In
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to find the point where “go” and “no go” in- times comes from one side, sometimes a fitting epilogue to the course topic, the
tersect. And the traffic cones keep flying. from the other. If you get the jolt while trav- weather provides plenty of µ-low the next
The last exercise is also an adrenaline eling at fifty km/h (31 mph), you’d better morning on the way to the birthplace of the
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stimulator. Before you get to the “car steer the other way pretty fast if you want first Porsche in Gmünd. The newly acquired
wash,” which runs as straight as an arrow, to keep your Porsche going the same di- knowledge can now be applied under real-
a “jolt trap” built into the pavement gives rection. And it doesn’t really matter if the life conditions. “I didn’t believe I had learned
the sports car a brutal sideways kick to the observer can see the understeering or hear so much,” says one participant thoughtful-
rear axle. The result is amazingly simple. the oversteering. The fact that the driver ly, “but after the drive here I know how
The coup de fesse, this decisive shot to has tried to steer at all is an accomplish- much it really was.”
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