Will Gray

Tech Talk: The changing challenge of Korea

Will Gray

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Last
weekend's Korean Grand Prix was a battle between Red Bull and McLaren with
unpredictable tyre wear the focus of their strategies - so how did they adapt
to the constantly changing track conditions?

The Korean
track sees very little running during the year so has one of the 'greenest'
surfaces on the calendar, with a combination of dusty track and an abrasive
surface resulting in massive grip level changes when the track 'rubbers in' as
the weekend progresses.

In 2010,
the fastest lap time between first practice and qualifying changed by more than
five seconds compared to about 2.5 at normal circuits, where that change comes
as teams develop their set-ups to suit the conditions.

Rain on
Friday this year made the three hours of practice irrelevant for dry data and
not only was the time for teams to collect data on race tyre wear cut to just
one hour of dry practice before qualifying, the track grip was also
dramatically changing right into the race.

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A Red Bull Formula One mechanic checks air pressures of tyres in front of a Swiss bank UBS sign at the pit lane at the Suzuka circuit
RUBBERING IN

The term 'rubbering
in' is, as it sounds, to do with the transfer of tyre rubber into the track.
This happens when the abrasive track surface interacts with the soft tyre
material under compression of tyre loading - and more track-embedded rubber
means more grip on the racing line.

Rain can
wash away that rubber, increasing lap times again by up to two seconds, but if
there is no rain the track will just see an increasing amount of rubber laid
down and compacted on the racing line through the weekend, with more effect in
corners due to the greater forces in play.

Mercedes
came up with some interesting stats before the Korea weekend, focusing on
sector times and showing that the grip increases during the 2010 event were
most significant in the second and third sectors, where there is more cornering
than sector one.

The second
element to track improvement is cleaning, as an unused track will collect dust
and debris (with Korea's lack of running making it one of the worst for this)
but that will be removed during a weekend as cars either pick it up on the
tyres or blow it off the racing line.

All of this
makes for an increasingly quicker racing line as the weekend progresses but
also an increasingly slippy off-line track as the rubber also gets torn and thrown
off the tyre as 'marbles' and they add to the uncleared dust and grit to reduce
the grip in that area.

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McLaren Formula One driver Lewis Hamilton of Britain leads Red Bull Formula One driver Sebastian Vettel of Germany and the pack off the grid the first
RACE VERSUS POLE FOCUS

Teams
usually have a large database of detailed information for regular venues,
allowing them to determine how the grip should develop at that track in
different conditions - but as it is just Korea's second year there is limited
data, particularly given the wet 2010 race.

Ahead of
the event, Pirelli talked of an aggressive approach to tyre selection having
chosen the two softest of their four tyre options.

They warned
that the supersoft tyres faced their "toughest test of the year"
because of the abrasive surface and the high lateral loading and predicted many
tyre stops for those focusing on the supersoft tyres rather than the soft
compound.

Expectations
were for the supersoft to work well for 10 laps before hitting 'the cliff' and
for the softs to last for 20, with a speed difference of around one second
between them.

After the
Friday rain, the one-hour session before qualifying saw Red Bull and McLaren
take an intriguingly different approach - with Red Bull concentrating on
analysing race pace and McLaren focusing on developing the optimum qualifying
set up to secure pole.

McLaren ran
a traditional strategy in qualifying but Red Bull elected to take a different
tack, running on supersofts all the way through and saving three sets of unused
softs for the race - so McLaren put five laps on one sets while Red Bull kept
their equivalent set new.

The result
was a McLaren pole position but a surprisingly happy Red Bull team, despite
failing to secure the top spot in qualifying for the first time this year.

As it was,
it quickly became apparent when the race began that the degradation was not as
high as expected and both types of tyre would last longer than the strategies
the teams had planned for - making the cunning move in qualifying redundant for
Red Bull.

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A Red Bull Formula One team member holds out an information board for driver Vettel of Germany as he passes the grid during the South Korean F1 Grand
Red Bull
still claim the race preparation in Q3 was crucial in their success, but
McLaren countered that what they learned from monitoring the lap times of the
entire grid using their complex data analysis tools was good enough to steer
their strategy through.

In the end,
both teams adopted a similar strategy so it was more a combination of luck and
skill from Vettel that secured the victory - with a superb pass on Hamilton on
lap one putting the German into the lead and aero issues hampering Hamilton later
on.

But the
point of Red Bull's qualifying tactic was it allowed them more strategic
flexibility - and although they didn't use it, predictions had pointed to
significantly changing grip levels through the 55-lap race, and that
flexibility is why they were smiling on Saturday.

 

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