How To Drive Your Tires To Go Fast - SHAKEDOWN University


Uploaded by drive on 06.07.2012

Transcript:

It's time for a mid-season Shakedown University.
Today, it's all about how to go fast, driving a racing
tire, and a street tire.
But in my version, you're taking the same
approach for both.
To get there, we'll talk a bit about tire management, how to
set up the car, and adjust the tires for max tire
performance.
And the real bottom line, how to feel what the tire is doing
so you can go fast.
We'll cover slip angles, the friction circle, tire
pressures, and camber thrust.
And most important, we'll get you to understand the value of
being smooth, precise, and sensitive with your pedal and
wheel inputs.
Fresh from my visit with Pirelli, we've got some
insights into their F1 tires, and talking to a few of their
pro racers, some tips on how to go freaking fast.
Now, I'm sorry we're doing this from a studio, but it's
all about knowledge and you putting the knowledge to
practice, experiencing it firsthand.
That's how you'll learn.
It may make for better video watching me drive, but focus,
my little Alonzos.
This ain't about me.
It's about you.
So get ready.
Our outlap starts when we come right back.

Let's get the first key lesson planted into your head as to
the dynamic we are trying to create when driving fast.
Whether you're on a race tire or a street tire, the
objective is to get the tire to its maximum limit of grip
as soon as possible, in any move, braking, cornering,
acceleration.
That means our moves with the car, and its controls--
the pedals and wheel--
are to be fast, firm, and precise, and at the limit.
I'll explain.
But I will say this right here, right now.
To go fast, you do not beat on your car.
You do not drive it like you stole it, or throw it around
like you're Liam Neeson roughing up the bad guys in
those Taken the movie fight scenes.
No.
Your moves with the wheel and pedals are fast and quick, but
to the max, like Liam.
It may sound violent.
It may feel abrupt to your passengers in the car, but to
the car, and to you, it's still smoothly all in control,
which is why we'll explain the friction circle first to
further plant into your head what we are trying to
accomplish with this hard, precise, smooth driving thing.
To start, think of your car as your hand, a platform to
balance as you break, corner, and accelerate.
The goal is to manage the weight transfer, to control it
with the goal of putting the weight to work where you want
it and need it-- again, getting it all to the max.
Now let's get to the friction circle, which is our metric to
understand that the tire only has so much grip to give.
What I mean is this.
You can get 100% of the tire's performance on braking or
acceleration in a straight line.
You can get 100% of the tire in cornering to the side.
But if you combine the dynamics, and that mix of 100%
allocation gets moved as percentages between the two.
So on the friction circle, that sends the grip, or
G-load, off in a tangent between the x and y vectors of
acceleration and cornering, or braking and cornering.
Now you can find such telemetry on many driving SIMs
and practice that yourself.
Trail braking, for example, is such a blend.
It has you keeping pace on the track.
It gets you slowed down.
A late apex opens up the corner so you can accelerate,
because you don't need all the maximum tire grip to get
around the corner.
Point is, think balance and grip within the friction
circle concept.
Now thinking is one thing, but feel is the visceral sensation
you need to read the tires, and by extension, the car.
And that gets us to slip angles, the angle where the
tire is pointed versus where the tire is going.
Now each tire has a slip angle for maximum grip.
Radial tires have smaller angles versus bias-ply.
And race tires have the lowest slip angle of all, so race
tires require the most precise steering.
But--
and here's where I may sound heretical--
even street tires with their bigger slip angles respond
best to little inputs versus big swipes at the wheel.
Because we're dealing with single-digit slip angles--
2 degrees or lower on race tires, 6 degrees and maybe a
bit more on performance street tires, and 50 degrees on any
tire brand with a name that has 12 consonants for every
vowel and way too many Ys, Zs, or Ks.
That was a joke.
Back to slip angles.
The rookie driver will slide the car beyond the ideal slip
angle and then pull it back.
The better drivers will nibble up to the max slip
angle/limit, but not go over the max grip, and therefore
not lose lap time.
And I'm saying that the same precision works on all tires.
You don't get an extra margin with street tire slip angles.
Oh, and practicing in the rain and snow will polish your
precision skills.
Keeping that sensitivity that you practiced in the wet,
using it in the dry will deliver the benefits.
Not letting the grip of a race tire fool you into going all
Monza Gorilla on the wheel is a good bet too.
And think of the pedals as a rifle trigger, not a
sledgehammer.
You know, unless you're McNish driving his R18 or
Vettel in his RB8.
Then the down force allows you to sledgehammer the brakes
like the Thor you are.
Let's watch Josh Vietze on our simulator here get a little
bit of this car control, and over-steering, and using slip
angles to their advantage.
When Josh Vietze isn't editing here at Drive, he's one of our
resident SIM drivers.
He's in his little launcher, here, and he's going to give
us two laps, one around this alpine course, a sloppy lap
with a lot of slip angle, and a lot of steering, and
probably a heavy foot on the gas and brake.
And then we're going to do a clean lap, comparing lap times
to show you where the speed is found.
So this is going to be an atypical Josh lap, a dirty
lap, high slip angle, a lot of steering work,
overdriving the car.
[DRIVING SOUNDS]
I can hear the tires working, overworking.
He's moving beyond that slip angle, beyond maximum grip.

Heavy-footed into a brake zone, locking it up.

Last corner, scrubbing off speed, over-correcting.
All scrub, comes into the final lap.
A 1.097 is not bad.
OK, Josh, now get ready and give us a good clean lap,
proper slip angles, precise wheel movement.
[DRIVING SOUNDS]
Targeting a 1.096 on the sloppy lap, and his best time
here, 1.083.
Point made.
Thank you, Josh.
Go back to work.
Thanks, Josh Vietze.
By the way, that was not a Simraceway SIM.
We'd still like one in our studio, hint, hint,
Simraceway.
But if you go to the Simraceway blog or their
website, you can take advantage of their test-drive
promotions, discounts on great cars like
the Boss 302 Mustang.
Plus they have new tracks, like a Dubai street circuit,
the Sonoma Raceway, and the karting track out there, and
Lime Rock Park, where I'm at right now as you're watching
this video.
So there you go, a promo and corporate begging for our
studio simulator, all in one paragraph of copy.
Back to the tire management discussion.
The ability to go fast is directly proportional to the
confidence you have in your perception of the gap in the
slip-angle threshold between "I got it" and "Oh, my God."
To control that gap, feel the tires through the wheel and
the pedals.
Yes, I said the pedals.
Think about it.
Now let's talk tire pressure, as that controls feel and
performance.
I'll spare you with the under- and over-inflation
ramifications.
You're smart enough to know all that.
But tires are springs, so the more pressure you put in the
tire, it becomes a tuning tool for the car.
More pressure also quickens the tire response and lowers
rolling resistance.
Tire temperatures.
I got a chance to talk to a few of the pro racers at the
Pirelli Track Day when I was back in Spain, Lucas di
Grassi, Felix Porteiro, and McLaren MP4-12C GT3 racer
Alvaro Parente.
Yep, my brother from another mother,
but a different country.
He's Portuguese.
I'm Italian-American, but who knows if my dad slept around.
[LAUGHS]
So running a tire within the temp range is obvious.
Again, it's all about slip angles.
With a race tire, I love how you can feel the tire temps
come up and the tire build grip.
And remember, high slip angles generate more heat, which may
be a useful fact when you're warming up the tires, but may
not be the best way to race the tires.
di Grassi, the guy who's doing the Pirelli F1 tire testing,
said, once the tire is cooked, not every tire can cool and
come back to life.
And Vettel in our New Jersey visit for that Grand Prix,
told me that the ideal temp range is more or less 10
degrees, and he's dealing with a working
threshold of 220 degrees.
And the current F1 Pirelli tires do fall off the cliff as
they wear, and the drop-off is immediate.
Now you know when the tires will go off based on
stimulation data, based on the pressures you're running, and
the car setup.
Then you just count the laps and watch the lap times.
The Pirelli is working to make the 2013 tire they're going to
produce more progressive in that drop-off.
The last piece to cover today is camber thrust, the angling
into the tires to enhance the lateral Gs
that a tire can generate.
Radial tires being more compliant means that more
camber is useful for them versus a bias tire.
So remember that when you're driving old cars versus new
ones, maybe online or in the real world.
The whole point of camber is to create a flat-tire
footprint in the corners.
In effect, the camber stands up the tire when you
angle the car in.
Monitoring even tire temps across the tire will help you
know how well the tire's working.
Front camber will help with turning.
Rear camber will help with stability of the car.
More camber in front versus less in back can affect
turn-in of the car.
We're going to do more on setup in another Shakedown.
But for now, for today, know this.
Camber will help with tire feel And
that's today's message.
The more clear the tire feel, the more precise you can be
with the car.
The more precise you are with your inputs, the more
performance you'll get out of the tire, and the faster
you'll go for longer.
It's really as simple as that.

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