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Formula One dances out of the
groove at the Brazilian Grand Prix, where grooved tyres are scheduled to bid
farewell from the sport they have been part of since 1998.
 Grands
Prix are set to take place on Bridgestone’s slick Potenza racing tyres from
the start of the 2009 season after the sport’s rules were changed to allow
the return to slicks, after eleven seasons of grooves.
Grooves were introduced as a means to slow cars which they achieve by having
a smaller contact patch with the road for any given tyre size. A smaller
contact patch means less grip with the road and also means that the rubber
that is in contact with the road has to be harder.
After the Brazilian Grand Prix has played out, Bridgestone’s grooved racing
tyres will have been used at 188 Grands Prix, and at countless Formula One
tests over the eleven years. When they were introduced it was a new concept
for motorsport, and one born of regulations rather than evolution.
“Developing grooved tyres was very exciting for us as we only had experience
of slick racing tyres,” explains Hirohide Hamashima, Bridgestone Director of
Motorsport Tyre Development. “We had the challenge of developing a tyre with
a hard compound because of the structure and tread profile of the tyre, but
one which gave the good grip required for Formula One.
“From an engineering perspective it has been a very interesting aspect of
our motorsport activities. We began testing our first grooved tyres in 1997
with Damon Hill. The first tyres were a modified slick tyre to let us
understand the differences and requirements of a grooved tyre.
“We soon found that the wear rate on the front tyre was very high, and we
experienced a lot of graining, so the compound we used for this tyre would
have to be a lot harder.
“The data we gained also proved to us that we would need a very strong
construction of front tyre. We redesigned the size and shape of the front
for a wider tyre and one with a larger diameter. This worked very well and
we could manage car behaviour better than with the previous size.”
The changes to the regulations for 1998 were not limited to grooved tyres
being implemented, as the regulations also saw the implementation of
narrower cars to reduce downforce. The changes presented the teams’
designers with many challenges.
“One of the teams we were going to supply for 1998 was McLaren and their car
had already been designed for the smaller front tyre size,” explains
Hamashima. “We had a lot of discussions with their chief designer, Adrian
Newey, about this as he was very insistent that he wanted to keep the
smaller size, however after the first test he accepted the concept and
modified the car.
Grooved tyres proved to be good for Bridgestone with the first pole
position, race win and fastest lap all achieved in the very first race of
grooves, the Australian Grand Prix. These feats were all achieved by McLaren
Mercedes driver Mika Hakkinen, who went on to win the world championship
that year, the first using Bridgestone tyres.
“1998 is a very memorable season for us,” says Hamashima. “We faced a
competitor, Goodyear, which had been in Formula One for many years, but
there were new regulations and we gained the advantage.”
For the next two seasons Bridgestone was the only tyre supplier for Formula
One, and this brought the additional challenge of supplying all of the teams
on the grid with grooved tyres.
“We faced a big challenge for 1999 as we found ourselves supplying all of
the teams in Formula One, and this was a big logistical step for us,”
explains Hamashima. “Then we faced a stronger challenge when a new and
hungry competitor entered Formula One.”
Michelin entered Formula One in 2001 and the development of grooved tyres
really took off. “The competition between our two companies was intense and
our understanding of these tyres increased at a rapid rate.
“We developed a new construction concept which allowed good grip but less
wear to counter the grooved tyre characteristics, and we had a big battle
with our rival tyre manufacturer with this tyre,” says Hamashima.
How a grooved tyre interacts with the road is different from the way in
which a slick tyre works and for drivers it was a new sensation.
“Driver comments when we moved to grooved tyres were not so favourable,”
explains Hamashima, “as drivers always want more grip, and grooved tyres, by
design, have less grip. Also, grooved tyres mean that graining is far more
likely and this means something else that drivers have to control in their
tyre management.”
Graining, where sideways forces mean the rubber rolls across the tyre,
changes the grip characteristics of the tyre when it is occurring.
“Graining is more common on grooved tyres as the compound is harder and more
difficult to get working on a dirty track,” explains Hamashima. “The grooves
also mean there are many edges on the tyres for the raised areas. Slicks are
less susceptible as there are no edges, the compound is softer and there’s a
bigger contact patch.”
Bridgestone was once more the only tyre supplier in Formula One for the 2007
season. “When we provide tyres to all teams the philosophy is different,”
explains Hamashima, “as we are no longer constantly developing compounds and
constructions to make faster tyres.
“Instead, we work to ensure that our tyre supply is fair and our tyres are
consistent for all teams, for example, by providing tyres for each race
which are made in the same batch.”
Bridgestone’s supply of grooved tyres to all of the teams through 2007 and
for the current season, which is the first of three with Bridgestone as the
Official Tyre Supplier to the FIA Formula One World Championship, has meant
lap times have got closer and closer.
“We saw at the start of the 2007 season that some teams quickly understood
how to maximise the potential of the different compounds and the strategy
options these allowed, whilst some teams took longer to develop their
understanding,” says Hamashima.
“However, as we approach the end of the 2008 season we can see that there is
very good understanding of our grooved tyres by all teams and lap times can
be very close.”
It’s all change for next season however, and Bridgestone’s focus is now on
slick tyres. “The return to slick tyres means we can apply the lessons
learnt from grooved Formula One tyres to slick Formula One tyres,” says
Hamashima. “2009 should be a very interesting season." |
