Driver Skills Student Guide
"The essence of high-performance driving, be it on the
street or on the race-track, is to control weight
transfer in order to maximize traction during the basic
functions of braking, cornering, and acceleration."
-Bob Bondurant,
Bob Bondurant on High Performance Driving
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Welcome! Today we will be teaching and practicing the fundamentals of
driving skills that will enable you to properly control the performance
of your car. As you can tell from the quote above, performance driving
is not about racing. Rather, it is about knowing how to handle your car
in any situation where you may find yourself driving at the limits of
traction. You don't even need to be going that fast. An unexpected patch
of ice, rain on oily streets or even just a little loose sand or gravel
on a nice dry road - any of these can suddenly turn a very mundane
maneuver into a critical situation demanding quick, sure responses. That
is why mastering these fundamental driving skills will make you a safer
driver overall, as well as helping you get the most from other club
events such as track and auto-cross.
First, lets be clear that the skills we will be working on today
really are fundamental, not advanced racer techniques or professional
stunt-car driver tricks. In Germany you would have to demonstrate
proficiency in these same skills just to get a drivers license - and
they require you do so in both fair and inclement weather! If you are
interested in track or autocross, these skills will give you a sound
foundation on which to build. If you just want to feel more confident
driving your car on the street, we think you will accomplish that easily
and have a great time while you're at it. You'll learn how to stop as
fast as possible - even on a curve! - and how to control that unexpected
skid. And you'll get lots of practice too, because knowing is not
enough. To drive well in tough situations your responses have to be
automatic.
So, what are we going to be doing today, and why?
Simply put, we'll be exploring traction limits in a progressive way
that will develop an intuitive feel for how our cars respond, in order
to make us better, safer drivers.
A key trait of a good driver is the ability to recognize the feel of
approaching traction limits. It all comes down to where the rubber meets
the road- the tire contact patch. As this little patch of rubber gets
stressed- from braking, say- it starts complaining. At first you just
hear a little scrubbing sound. The tire is starting to "work". Push it a
little harder and it starts to squeal. This is the point at which the
contact patch is just barely sliding a little. It's not sliding much, so
you still have control. This represents maximum traction for most tires
and is the reason Bob Bondurant says "a squealing tire is a happy tire."
When pushed beyond this point tires start to howl. You are sliding!
The two most important things we will teach you today are how to get
your car into tire-squealing mode in a controlled manner- quickly,
smoothly and consistently- and just as importantly, how to respond when
the tires howl and you are sliding. We'll start with the two simplest
situations: straight line braking and steady-state cornering. Next,
we'll throw in turning while braking, and give you some experience
learning the effects and control of weight transfer while cornering.
Along the way we are going to try and get you looking where you want to
go.
In the second half of the day we'll really get into the art of
controlling weight transfer. Using two ovals we'll work on how to
maximize traction while cornering safely, and practice controlling
over-steer and under-steer. Finally, we'll work on spin-control (not the
Clinton kind!) and heel and toe downshifting.
Things to check before you start driving
Here are a few things to check before you even start driving. At some
point during the day you may want to have an instructor go over each of
these with you:
- Remove or stow anything that might shift around while
driving!
Check under and behind seats. Don't forget the trunk either- a loose
jack or wrench is not only noisy, it might even damage your car.
- Check your seating position carefully.
There should be a slight bend in your knee when fully depressing the
clutch. You should be able to place both wrists on top of the
steering wheel while keeping your shoulders in full contact with the
seat back.
- Check tire pressure.
Cars and tires vary enough that you'll have to determine for
yourself what your ideal tire pressures are. They should be the same
from side to side of course, but the ideal front/rear differential
depends on several factors. Also your tire pressures will change
throughout the day, as the tires heat up. This is something you will
want to check frequently and experiment with until you get a feel
for what works best for you.
- Check your mirrors.
Your rear-view mirror should give you a view directly behind you.
Your side-view mirrors are NOT intended to duplicate this view!
There should be some overlap, but if you can see the side of your
car they are probably not pointed far enough out
The first three exercises are all designed to gain handling
experience at the limits of traction, in relatively simple situations.
When you know which station you'll be doing first, start reading that
section. The best strategy for getting the most from this program is to
concentrate on reading the guide, driving, and talking to instructors
and the other drivers. Then, just before you begin each run, take a
moment to relax, focus on what you are about to do and visualize
yourself doing it. OK, lets get going!
Threshold Braking
Threshold braking. Doesn't that just sound a heck of a lot cooler
than stopping as fast as you can? You know you are in a professional
situation when the instructor says "demonstrate threshold braking"
instead of "hit the brakes!" So what exactly is the difference
between threshold braking and slamming on the brakes? Well, for one
thing, it has to do with how you control weight transfer.
Consider what happens when you are just cruising along and then
suddenly slam on the brakes. The car starts out with just a light
load on the front tire contact patches, when suddenly this
tremendous braking force is exerted on the brakes. The tires stop
turning. You are slowing down, but with no directional control
because the tires are skidding. As the cars weight transfers
forward, the increased pressure on the front will give you more
traction, helping you stop faster. But because that weight has
transferred forward there is now much less weight at the rear, so
those tires also start to skid. The simple act of slamming on the
brakes has transformed your Porsche into a ballistic object with all
the responsiveness of a Seriously Unmaneuverable Vehicle!
Now lets try threshold braking. Squeeze on the brakes by
increasing braking pressure quickly but smoothly. As braking forces
build up the increased weight transfer forward is compressing the
suspension, giving you progressively more traction on the front
tires. Because you are squeezing smoothly these forces will build up
smoothly, allowing you to control them. The tires are going to start
squealing! At the first hint of tire squeal you immediately begin to
modulate the brakes, easing off just the tiniest bit to avoid
skidding and then squeezing again, keeping the tires working at
their limit. Now you have fully loaded the front suspension, getting
the most traction possible from the front tires, but because the
brakes are not fully on you have little risk of locking the rear
wheels. Tires squealing merrily, modulating the brakes skillfully,
you maintain full control the whole time while stopping in the
shortest distance possible.
Our first threshold braking exercise is simply to practice
stopping in a straight line in the shortest distance possible.
Accelerate to 50-60 mph. Be aware of your speed and be consistent
each run. This will make learning easier and make your stopping
distances more comparable. Begin braking at the marker cone and note
where you end up on each run. Your goal is to be able to initiate
threshold braking (tire squeal) quickly, maintain it until stopped,
and do this consistently enough that your stops are no more than
about 5 ft apart. When you can do this several times, talk to your
instructor about trying it a bit faster- 70 mph max!
Our second exercise is meant to emulate braking to enter a
corner. This time, instead of using a cone to tell you where to
start braking, you'll have to figure this out for yourself. The goal
is to stop your car at the same point each time. Remember, you must
threshold brake all the way until you are stopped! Do not ease onto
the brakes and do not ease up if you see you are going to stop too
soon. Stop as fast as you can each time. If you stop short, brake
later next time. Talk to your instructor about trying different
speeds if you are consistently within a few feet of the cone.
The third exercise combines braking and cornering. You
really need to maximize traction in order to corner while braking.
And what is the key to maximizing traction? Controlling weight
transfer! When threshold braking you are using every bit of
available traction just to stop in a straight line. All your weight
is going forward. Now if you simply turn the wheel, what happens?
The cars weight shifts outside, putting less weight on the inside
front wheel, which promptly locks up. To maximize traction, ease up
on the brakes as you begin turning in. Continue easing as you turn
and more of the cars weight transfers onto the outside tires. Coming
through the turn, increase braking again as soon as you feel the
cars weight balance coming back.
This is a balancing act. The front end, especially the outside
front tire, has lots of traction because of weight transfer. But you
are asking it to do so much that despite all that weight it is
pushed to its limit. The rear end is so light from weight transfer
that even though you are just asking it to follow along, it is
barely able to do even that much and is threatening to spin around
on you. You can lock the inside front in a split second or spin the
car if it gets off balance. Is this fun, or what??!
Done properly, you should hear the fronts squealing under
threshold braking. The sound will change as you begin turning in and
the outside front takes on more of the load. There will be a
transition point where, if you are right at the limit, you will hear
one or both rear tires squeal briefly. Then you are through the turn
and back to front tire squeal until you stop. Other important
feedback comes from your seat, informing you of the cars attitude,
and your steering wheel, which will give immediate feedback if the
inside front locks.
Check your tire pressure. The tires
will have warmed, probably increasing pressure by a pound or two. Is
the front/rear balance where you want it? Which tires heated up
most, front or rear? If you haven't formed any clear impressions yet
then either leave it alone or let just enough air out to get back to
where you were at the beginning of the day.
Skid-pad
The skid-pad is a cornering lab. We'll develop quite a few skills
on this simple circle:
- Looking ahead to where you want to go.
- Using smooth steering and throttle inputs.
- Getting your car into its maximum cornering stance.
- Using throttle steer to change your line.
- Controlling under-steer and over-steer.
- Understanding how tire pressure affects handling.
If you've been paying attention then you've probably noticed that
four of the six bullet points above pertain to controlling weight
transfer! That's right. Your cars maximum cornering stance is simply
the attitude of the car when its weight is distributed onto the
tires so that it maximizes traction for a given cornering situation.
Under-steer and over-steer result when that balance is off.
Skid-pad exercise #1: steady-state cornering.
Accelerate very gradually until the tires start working. Notice
how steering is affected as the tires work harder, how the balance
of the car shifts, the way the suspension gets settled if you are
steady, unsettled if you are jerky. As soon as tire scrubbing is
heard, but before they start to squeal, carefully ease back the
throttle and do a few laps with the tires just scrubbing. Notice how
if you get just a bit off line and correct too quickly you get tire
squeal? Concentrate on smoothness, using very fine inputs to
maintain the cars attitude. Look ahead, not from cone to cone,
concentrating on maintaining a steady, precise circle. Try to do
several laps of steady tire scrubbing without tire squeal and
staying within a few inches of the line.
Next time out bring the car up to tire scrubbing speed a little
more quickly. Do one or two nice, steady laps. Then carefully roll
on the throttle, very gradually increasing speed until the tires are
squealing nicely. Ease back and do a few laps, trying to keep a nice
steady squeal going while staying precisely on line. Listen to your
tires and engine. Feel the feedback coming from your seat and
steering wheel. There is a lot going on when cornering at the limit,
even on a flat, repetitive circle. Listen to your car and learn.
Finally, try pushing your tires really hard. Roll on the throttle
from tire squealing speed. Something's got to give! This is where
you find out if your car is balanced towards under-steer or
over-steer. You may reach a point where as you try and accelerate,
the car goes wide even if you try steering in tighter. That is
under-steer. Or you may find your rear end sliding out on you. That
is over-steer.
Check your tires. Look for the freshly-scrubbed edge from
the cornering you've just done. It should be just past the shoulder
of the tire, the point where the flat tread starts to wrap around
onto the side-wall. Let some air out if you are barely scrubbing the
shoulder. Put some air in if there is scrubbing beyond the shoulder
too close to the side-wall. This is a judgment call, so talk to
others, watch what they do and most of all, pay attention to how any
changes you make affect your car's handling.
How tire pressure affects handling.
Lets say you have been taking the advice above and got your tires
pretty close to where they should be. Now you notice on the skid-pad
that your car tends to under-steer. This can be fine-tuned a bit
with judicious adjustments to tire pressure. To correct an
under-steer tendency, either reduce rear tire pressure or increase
front tire pressure. To correct an over-steer tendency, either
increase rear tire pressure or decrease front tire pressure. Which
is best? I knew you'd ask!
Changing tire pressure affects more than just absolute traction.
It also affects responsiveness. With higher tire pressure you will
notice quicker responsiveness, better feedback and road feel. So if
you want to tame under-steer tendency and your car feels a bit slow
up front, then put more air in the fronts. But if the steering
already feels very lively and responsive, then try decreasing rear
tire pressure. Make small changes, no more than 2 psi at a time.
Skid-pad exercise #2: throttle-steer.
Throttle-steer refers to the balance or tension between throttle
and steering over which way your car will go. In other words, when
cornering at the limit it is not only steering that determines your
course. Throttle control also affects your line. Why? Weight
transfer!
The goal of this exercise is to become familiar with the effects
of throttle-steer. Bring your car up to speed, staying inside the
center-line. When you are ready, roll on the throttle moderately, as
if accelerating out of a corner. As weight transfers to the rear the
front end will get light and start to slide. This is under-steer. Do
not steer in the direction of the slide! Keep the wheel turned in
tight, paying attention to the feel of the wheel and the cars
direction of travel. Throttle is pushing the front end, forcing you
into a wider line. Ease off as you start to cross the center line,
letting weight transfer restore traction and steering.
Notice how the steering got light as you entered under-steer?
First the steering gets a bit light as weight transfer lightens the
front, giving less traction. Then as the fronts start to slide they
have a lot less traction, so steering feel gets even lighter. If you
are quick about it you can even "wag" the front wheels by turning
quickly in (as if you want to go tighter) and back again. Doing this
won't upset the car because the front's ability to control direction
is so overwhelmed by throttle.
Experiment with different amounts of throttle and steering input.
Get used to feeling the front end slide. Pay attention to balance.
Learn to use just enough throttle, no more than is necessary to go
where you want to go.
Next, over-steer. While cornering hard at the center-line, lift
right off the throttle. By now you should know what to expect- the
rear end is going to get light and start sliding very quickly!
Immediately make a quick steering correction in the direction of the
skid. It doesn't have to be a lot, just enough to get the front back
in line with the rear. Then smoothly bring back just enough throttle
to restore balance.
What happened? Coming off throttle lightened the rear, initiating
the slide. Quickly steering in the direction of the skid stopped the
rear end motion from developing into a spin. The sliding rear end
scrubbed off some speed, so that once throttle was restored
everything comes back into balance allowing continued cornering
though at a lower speed.
Skid-pad exercise #3: advanced throttle-steer.
I lied. This isn't really advanced. Its the same stuff you just
did. Only now we want you to do it a lot better. More consistent.
More precise. More deliberate. Better.
Here's what to do. Start inside. Use throttle-steer to widen your
line, power into the outside lane and settle into maximum cornering
there. Then lift quickly and briefly, this time using throttle-steer
to bring the rear end out just enough to tighten your line,
scrubbing off just enough speed to allow the car to quickly settle
into maximum cornering attitude in the inside lane.
Practice changing lanes from the inside to the outside and back
again, repeatedly, without skidding and with only the briefest
lapses in tire squeal. Listen to your tires and remember the
scrubbing sound means you are approaching your traction limit,
squealing means you are right on it and howling means you have
passed the limit. Try to keep the tires always at least scrubbing,
i.e. close to the limit, while doing these maneuvers
Avoidance Maneuver
Ever notice how even the most minor little accident can snarl
traffic for miles? After an eternity of waiting you finally get to
where the big wreck should be, and it's just some little car off on
the shoulder ran out of gas! Its clear off the road, impeding no
one. But then just as you are ready to accelerate past, the road
ahead finally almost clear, that's when you see the car ahead of you
practically rear-end the car ahead of him! What are these people
doing?!
Well, they're not looking ahead, that's for sure!
This little exercise is about just one thing: if you want to
avoid an accident, look where you want to go! Don't look at
the accident or you will be the accident! This isn't just about
avoiding accidents, either. Looking ahead to where you want to go
helps you be smooth and fast on the track or auto-cross and safer in
everyday driving.
In this exercise you will drive a slalom, skipping cones
according to a signal from the person at the far end of the slalom.
That person will occasionally signal you to skip a gate. The idea is
to train your eyes to look ahead while still being aware of what is
around you. Your first run should be taken very slowly and smoothly.
Weave through the slalom normally until you get the signal, then
smoothly change your line, getting set up to slalom at the next
cone. Increase your speed a bit each run but never push your comfort
zone. Remember the focus is on looking ahead, not car handling
skills.
If you decide to catch a little auto-cross action during lunch, make
the most of it. Watch the balance of different cars as they go through a
particular section. The fastest cars are coolest to watch, sure. But you
can learn just as much by watching the slower cars, because their softer
suspensions make it easier to see the cars attitude or balance.
Now we are going to start combining the skills practiced individually
earlier. We'll also introduce a couple new concepts: the late-apex
cornering line and heel-and-toe downshifting. Our cornering so far has
been simple, but that will change as we add braking and acceleration
while cornering. If time allows we may even introduce increasing and
decreasing-radius turns. Everything though still emphasizes the same
basic concept: controlling weight transfer in order to maximize
traction.
Line refers to the physical path a car takes around a corner.
Apex area is the section of a corner where a car is in its most
stable maximum cornering attitude. The apex is the point on a cars
line where the car is closest to the inside edge of the turn. As we
shall see, the late apex line is the safest and most efficient way
to take a corner. In most cases it is also the fastest way round.
This is just as true for the highway, where you want to use your
entire lane to maximum advantage, as it is on the racetrack where
the entire track can be used.
To see why this is so, take a look at the apex diagrams. The
early apex line cuts inside too soon, forcing the driver to have to
suddenly turn sharper right in the middle of the turn. Braking or
even just lifting off the throttle to do this will transfer weight
off the rear end, the perfect recipe for a spin. (A friend of mine
almost spun like this coming off 520 in the wet- while doing the
speed limit!) Even avoiding a spin, this is a slow line because
throttle can't be used until very late in the turn.
The geometric or middle apex line is what most people consider
the way to corner- go in wide, clip the inside exactly halfway
through, swing to the outside at the end. The problem here is that
if you misjudge speed or traction and find yourself going too fast,
you are going to run out of road. Not as bad as in the early apex,
but it will still happen. The other disadvantage is that again, you
can't get on the throttle until you are exiting the corner.
The late apex line enters the corner way to the outside and then
gradually comes in tighter, not clipping the inside edge until about
2/3 of the way around. Because most of the turning is done in the
apex area just about midway through the corner, by the time the car
is headed for the apex or clipping point it is nearly pointed out of
the turn. This means you can begin rolling on the throttle just
before the apex. If throttle steer widens your line it's OK because
the late-apex line allows room to do that.
Small Oval Exercises
The small oval will be all 2nd gear. First we'll work on driving
the late-apex line. Then we will explore traction limits, learning
to transition from threshold braking to cornering while setting the
car up to roll on the throttle through a late-apex for a fast exit.
Next we will work on generating and controlling over-steer and
under-steer. Finally, we will practice four-wheel drifts and spins.
And grins!
- Late-apex line. Driving at a moderate speed, follow the
late-apex line. Concentrate on smoothness and precision, not
speed. Gradually pick up the pace to where the tires just start
working. No hard braking. No hard acceleration. No tire squeal.
Not for now, that is!
- Turn-in. Now pick up the pace a little, so that some good
hard braking is required. Concentrate on controlling weight
transfer. Ease off the brakes as you turn-in. Get the car
settled on its chassis, on the late-apex line. Roll on some
throttle coming through the apex, but only about 3/4 throttle at
most.
- Throttle-steer and exit speed. Pick up the pace even more,
this time by gradually using more and more throttle. Controlling
weight transfer is critical here! Set the car up wrong, dial in
too much throttle too soon, and you are off-line and have to
slow down to save it. Concentrate on setting the car up to
enable rolling on the throttle earlier while staying on-line.
- Under-steer. Generate under-steer in a planned, controlled
manner. Get on the throttle too hard and early. As you get
"push" or under-steer the first few times, simply pay attention
to how it feels. When this becomes comfortable, prove it to the
instructor. Quickly "wag" the front wheels, turning the wheel
back and forth during under-steer.
- Over-steer. Generate over-steer in a planned, controlled
manner. Brake a bit late and turn-in a bit early, so that the
rear end is lightened too much for the corner. (That's right-
weight transfer again!) When the rear end starts coming around,
don't correct too fast. We want you to get the rear end out
there, at least a foot or three! Recover by steering in the
direction of the skid and rolling on enough throttle to restore
weight balance.
- Four-wheel drifts. Generate a small amount of over-steer,
only this time set the car up to use throttle-steer to control
the slide. Roll on enough throttle to keep the front end sliding
too, so that the car drifts around the corner. This is not the
fastest way to corner, but it is a great way to teach the fine
art of throttle control!
- Spins. Yes, we want you to spin. On purpose. Under control.
Spin the car to a stop midway around the turn. Remember- IN A
SPIN, BOTH FEET IN! Any time you reach the point where the car
is going to spin -- and that means more than 90 degrees to
direction of travel -- push the clutch in! Otherwise, if the car
goes backwards in gear you can get some serious engine damage!
Large Oval
The large oval will be used to practice heel-and-toe technique,
in addition to the small oval exercises. The focus is about half on
heel-and-toe, half on the other skills.
Heel-and-toe Downshifting
Its a common misconception that heel-and-toe downshifting is
about braking. Its not. That idea came from olden days when brakes
were poor and prone to fade and failure. Today's brakes are so much
more powerful and reliable, and engines so much more expensive, that
its foolish to use your engine for braking. Why then is heel-and-toe
downshifting important? Because it helps to control weight transfer!
Downshifting without matching engine revs to the lower gear will
cause the car to lurch, upsetting its balance. A real bad downshift
may upset things enough to cause a skid or spin. But smooth shifting
is important even in regular driving, if only because it increases
the useful life of expensive drive-train components. Heel-and-toe
technique is essential to smooth downshifting.
Here is the way to heel-and-toe downshift, step by step:
- Start braking, squeezing on the brakes with the ball of your
right foot.
- Move your hand to the shift lever and position your foot on
the clutch, to be ready to shift. Continue braking.
- Now push in the clutch and shift. As your clutch goes in,
pivot your right heel and roll the side of your right foot onto
the throttle.
- Squeeze on the throttle with the side of your right foot,
and rev up to just above where it was in the higher gear.
Continue braking as you shift, let the clutch out and roll off
the throttle.
- Pivot your foot back to finish braking after a nice, smooth
downshift.
Done properly, heel-and-toe downshifting can be so smooth you
hardly feel it. One key to this is learning to match engine revs to
your gear and speed. The more you do it, the better you will get.
You can even practice while droning along on the morning commute!
While cruising along at 60 mph in 5th, practice shifting from 5th to
4th to 3rd, back and forth, while maintaining a constant speed. This
does not involve braking but it will help develop a feel for the
car, ultimately enabling smooth downshifts without looking at the
tach, or even thinking about it. It will just become automatic.
Secrets of Smooth Shifting
With any luck, this will not remain a secret for long. The
secrets of smooth shifting are: throttle control and rhythm.
Up-shift or down-shift, it doesn't matter. The gas pedal is not an
on/off switch. When preparing to shift, don't just suddenly lift
completely off the throttle. Lift smoothly, at a rate and in an
amount appropriate to the rhythm of the car. Then when ready to let
the clutch back out to complete the shift, bring the revs back up
again by using throttle that suits the rhythm of the car.
A little more about the rhythm thing. Each car has a transmission
that shifts well at a certain rate. Try to shift faster and it feels
forced. Hard on the equipment and the chance of a missed shift goes
way up. Find the right rhythm of clutch-shift-clutch though, get
into that rhythm, and you will be smooth and consistent. And that
equals fast and safe. Likewise, each car has an engine that revs up
and down at a particular rate. Get into that rhythm too. Then bring
it all together and groove on the sublime smoothness of it all.
Heel-and-toe downshifting practice
- Heel-and-toe. Execute heel-and-toe downshifts while lapping
at a moderate pace. Concentrate on smooth shifting. This goes
for up-shifts as well as down-shifts! Drive the late-apex line,
keeping the speed down enough to allow full concentration on
smooth shifting.
- Braking and cornering. Increase the pace, with emphasis on
setting the car up on the desired line, as you become more
comfortable with heel-and-toe. Everything listed above for the
small oval applies here. When you have mastered heel-and-toe,
and with your instructors approval, proceed to practice those
same 7 skills here.
Congratulations!
You've just completed a very demanding course in the basics of
car control. You've learned some new skills, becoming a better
driver in the process. Now don't let it all go to waste! Come on out
and try Autocross or Drivers Ed. Or come back and try Skills Day
again, to see how much better you do. Until then, drive safely,
drive well, and most of all -- drive your Porsche!