Get Out of the Groove
Bridgestone is to work with slick rubber for the first time since 1997 in the 2009 Formula One season. Rule changes are to prevent the use of grooved racing tyres next season, meaning that this weekend’s season-closer in Brazil will be the grooves’ last stand.
Hirohide Hamashima, the company’s director of motorsport tyre development, explained the company’s 188 Grand Prix history with grooved tyres to F1 news sources: “Developing grooved tyres was very exciting for us as we only had experience of slick racing tyres. 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 development of the company’s grooved tyres enabled Bridgestone to claim its first pole position, race victory and fastest lap, all achieved by Mika Hakkinen’s McLaren. In 1999, Bridgestone supplied the tyres for every team following Goodyear’s withdrawal, a challenge Hamashima describes as “a big logical step for us.”
Competition between Bridgestone and newcomer Michelin “was intense”, he continued, speaking of 2001’s return to two tyre makers. The rivalry sparked a development contest between the companies, which resulted in great progress with grooved tyres: “We developed a new construction concept which allowed good grip but less wear to counter the grooved tyre characteristics,” states Hamashima.
Hamashima remembers that when grooved tyres were first introduced, F1 drivers were “not so favourable”, complaining that the new tyres did not yield as much grip – unsurprisingly, considering that the characteristic is a key difference from slicks. Graining also proved problematic in terms of grip, with the increased number of edges over slicks providing tyre management problems for the teams.
In 2007, Bridgestone once again took the reigns as sole tyre supplier. “When we provide tyres to all teams the philosophy is different,” Hamashima said, “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.” This consistency has allowed the margin of lap times to be closed consistently, as teams have got to grips with the grooved tyres’ performance. However, this could all be about to change with the re-emergence of slicks in 2009.
“The return to slick tyres means we can apply the lessons learnt from grooved Formula One tyres to slick Formula One tyres,” said Hamashima. “2009 should be a very interesting season.”