Hungarian GP, Friday,
The Renault F1 Team began its Hungarian Grand Prix weekend
with a competitive showing in Friday's free practice sessions,
with Fernando Alonso finishing the day second on the timesheets
and Giancarlo Fisichella third.
The cool track temperatures combined with the low-grip surface
of the little-used Hungaroring circuit meant both drivers
struggled for grip, and experienced tyre graining. However,
the engineers were able to make progress on stabilising the
car balance with a number of set-up changes, and will continue
to work in this direction tomorrow to achieve a neutral, driveable
in race conditions for what is always one of the most physically-demanding
Grands Prix of the season.
Fernando Alonso, P2, 16 laps total, 1:23.097
It was a good start to the weekend for me. The conditions
were very low grip today and that meant the car balance was
quite inconsistent, but we managed to do our normal programme,
get a feel for the tyre performance and start making some
set-up changes. I was having some problems with the rear end
to begin with, but we managed to calm it down during the session
and we will carry on working in that direction tomorrow. The
times seem competitive, so I think we are on the right track.
Giancarlo Fisichella, P3, 15 laps total, 1:23.189
I had a problem on my first lap when the traction control
cut out on the exit of turn 7 and I half-spun. But we fixed
it in the garage, and after that started the normal programme.
It's much colder than usual here in Hungary, and that means
the conditions are very low grip indeed, coming from the track
but also the tyres. The car was quite tricky to drive because
of this, but we made some good changes and need to do some
more overnight. It is going to be a difficult weekend because
of the conditions, but we seem to be in reasonable shape.
FRIDAY FOCUS: TYRE MANAGEMENT IN HUNGARY
Tyre management has been a key theme of the 2006 world championship
so far, and the unseasonally cool temperatures experience
today and forecast for the rest of the weekend at the Hungaroring,
have thrown a further spanner in the works for the teams.
Typically, the race weekend in Hungary is among the hottest
of the year, with high temperatures and lots of direct sunshine
heating the circuit to temperatures of around 50°C. Accordingly,
tyres for the event were tested and selected in the balmy
Mediterranean climes of Jerez and Paul Ricard. Today, however,
track temperatures barely reached 25°C with significant
cloud cover preventing any warming of the track surface. And
although sunny spells are forecast on Saturday and Sunday,
the temperature of the asphalt is still unlikely to exceed
35°C.
All this means every driver is likely to encounter, and have
to manage, the same problem: tyre graining. One cause of this
phenomenon can be tyres operating in cooler temperatures than
they were designed for; another can be low circuit grip which
means the tyres' adhesion is not optimum. Both could be factors
this weekend.
"Tyre selection is a complex process," explains
Renault's Executive Director of Engineering Pat Symonds. "Fundamentally,
tyre choice for an event is centred around selecting the compound.
A tyre's construction tends to be more universally applicable
from circuit to circuit, but the compound must be chosen with
knowledge of the energy the tyre must handle around an individual
track. The total energy is a function of how much work the
tyre must do around the lap – how many high-speed corners
there are, for example, or traction events. But the temperature
of the circuit is also a factor. If we encounter significantly
lower temperatures than we had expected, as is the case this
weekend, then the compound is forced to operate outside the
conditions it was designed for."
In cooler conditions, with the tyre running outside its operating
window, it is unable to generate the correct adhesive properties
with the track surface. As a result, graining ensues when
the tyre slides: the rubber literally shears off the tyre
and rolls up on its surface, usually at the front but sometimes
also the rear. Front graining means increased understeer,
and gradually disappears as the tyres wear (which ‘cleans
up' the ‘loose' rubber from the tread); rear graining
will leave the drivers fighting oversteer. The same phenomenon
occurs on a ‘green' track for similar reasons: with
little rubber on the racing line, the correct adhesive properties
cannot be generated and graining follows – as can often
be seen on the Friday of a Grand Prix meeting before any significant
running has been done.
So the key question may be, what can teams do to cope with
the graining this weekend? "It is a problem we are familiar
with from winter testing, which is usually conducted in much
cooler temperatures," continues Symonds. "One of
the keys is getting the tyres up to operating temperature
as quickly as possible, but there are also a number of other
tricks you can employ – for example, running with older,
worn tyres which are less susceptible to graining than a brand
new set. Typically, we would expect problems with graining
to reduce as the weekend goes on, but the cool temperatures
and likelihood of overnight rain means we may well encounter
this phenomenon during Sunday's Grand Prix. It will be a case
of coping with it as well as we can this weekend – and
trying to minimise its impact on how we run our race."
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