Pirelli's return to
Formula
One racing is rolling along Down Under at this weekend’s
Melbourne Grand Prix.
Most cars opted to use the hard P Zero tires in the first session, which have
been nominated as the prime tire for Australia, before
switching to the soft tire for the bulk of the second
session as the crews refined their racing strategies.
“We’re pleased with our first outing under competitive grand
prix conditions, as our tires have already shown a good
level of performance and durability,” says Paul Hembery,
Pirelli’s motorsports director.
“While the weather may have felt cold for Australia, these
were actually some of the warmest conditions that we have
run in recently, and already we can see that our rubber is
working better at these temperatures. We’re in for a very
exciting weekend: Even with all the information that we have
at our disposal, it’s still hard to predict exactly how all
the action will unfold.”
Compared to the supersoft – the most aggressive compound of
the range – the soft tire is 25 percent harder and the hard
tire is 170 percent harder, meaning that there is a 145
percent difference between the two tires available to the 12
teams in Melbourne.
“We’ve worked hard for more action together with all the
teams and now we can finally get going,” says
Hembery.
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“ It wasn’t easy to find the best balance in terms of tire
degradation, which would promote pit stops and enhance the
show, as we were requested, but at the same time ensure that
the tires did not deteriorate too rapidly or too slowly,” he
explains.
“In GP2, where the cars and the tires are quite similar to
Formula One, it was a lot simpler,” Hembery adds.
“The teams asked us for structural reliability rather than
variable degradation, and after the first few races we know
that we have come up with a long-lasting tire that everybody
likes,” he reports.
“What’s certain is that our P Zero Formula One tires are structurally
extremely reliable and can guarantee safety. The degradation
is not immediate, but it is enough for the driver to feel a
gradual drop off in performance over the course of a stint
and then decide whether to change tires or not. This is
where strategy comes into play. In Australia our target is
to see between two and three pit stops per car,” Hembery
points out.
The choice of the hard tire, which is the most durable P
Zero compound, was influenced by the characteristics of the
Albert Park track, which combines a medium aggressive
surface with constant changes of elevation, speed and
direction. For the same reasons, the soft tire has been
chosen too, he says, going on to provide additional details:
The Albert Park circuit, which is 5,303 meters long and
takes in 58 race laps that total 191.117 miles, is home to a
wide variety of conditions on a surface that is not greatly
rubbered-in. “This has a profound effect on tire
wear.”
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Another important factor governing tire wear is the
comparatively high level of downforce used, which is
necessary due to the quick succession of corners and absence
of long straights.
A place where the tires and cars are worked especially hard
is the Sport Centre corner. The drivers scrub off 124 miles
per hour in just 2.5 seconds and 108 meters under braking,
subjecting themselves to a 5G deceleration while the front
tires are pushed into the ground by 2535 pounds of
downforce.
Shortly afterwards there is another challenge; a long
right-hand corner that is taken flat-out, with slippery
asphalt that can provoke oversteer and therefore tire
wear.
The drivers then enter the most technical part of the track,
which is also the most demanding – a blind bend taken at
around 155 miles per hour, where it is important to stick to
the part of the circuit that is most rubbered-in so as to
take maximum advantage of the grip available. This is part
of an S-bend complex, with bumpy asphalt that can
destabilize the car. Being only a semi-permanent facility,
the track has very little rubber on it at the start of the
event, which has an inevitable effect on tire
performance.
Waite corner is one of the key points of Albert Park. The
exit speed from the corner is in the region of 130 miles per
hour. The stressed front tire (on the outside of the curve)
is operating at around 221 degrees F., whereas the inside
tire on the right has slightly less work to do and runs nine
degrees cooler at around 212 degrees. The rear tires, which
provide the traction, operate at temperatures in excess of
212 degrees.
Another important area is the braking zone between turns 14
and 16, which loads the front of the car heavily leading
into a chicane with tight right-angle corners before the
main straight; the only place on the track where the cars
top 186 miles per hour in seventh gear, and a key overtaking
opportunity.
The size of the tire’s contact patch with the ground varies
according to speed and aerodynamic load. At 186 miles per
hour the contact patch of the tire is around three times
what is when stationary, offering optimal traction and grip.
For more information, visit www.us.pirelli.com.