Slick tyres return to F1

"We are going to halve the downforce produced by the cars. To make up for the reduced grip this will cause, we want to bring back slick tyres."

This was how the FIA put it to us as they announced the new tyre regulations for 2009. Hamashima recalls that changing from grooved to slick tyres didn't actually involve any major technical problems.

"Back in 1998 we had already experienced the change from slick to grooved tyres. So to reverse that wasn't really a new challenge. And in fact we had already been supplying slick tyres for GP2, so we could use that as a base for our development."

However, a problem did occur during development of the slick tyres. The development engineers reported that, if the same size of tyre as 2008 was used, they couldn't prevent the front tyres from generating excessive amounts of grip.

During the changeover from slick to grooved tyres back in 1998, we had also asked the teams to change the size of their front tyres. Adrian Newey, McLaren's engineer known for his genius in aerodynamic design, refused to change, saying that his car's design was already complete. He would later change his mind after seeing the improvement in performance we achieved. This time conditions were reversed, but we had an easier time getting the teams to understand our reasoning. Even so, they all begged us not to change tyre sizes since they had already finished their 2009 car designs.

The difference from 1998 was that then we had been in competition with Goodyear, but in 2009 we were sole tyre supplier. Hamashima could only say "If everyone wants the same thing, we have to go along with them."

So, in practice, what changes were involved in the move from grooved to slick tyres? First was the compound. If we kept the same compound the rubber would be too hard, so we changed to a softer rubber.

Also, we changed the internal details of the four specifications we supplied. Our aim was to achieve a deeper understanding of how the tyres worked.

The four specifications were super soft, soft, medium and hard. We kept the same names as 2008, but changed the working ranges of the tyres. We divided these working ranges into two, and chose one from each to supply for each race.

Hamashima: "Unlike the previous year, we were now supplying just two types, covering the low and high working ranges. This allowed us to better study how the various compounds worked and use that as a base for future tyre development."

"How did different compounds work in each race? What was different between low and high working ranges? We were now able to fully investigate these questions."

In-season test ban spurs simulation technology

One of the biggest of the regulation changes for 2009 was the banning of tests during the season. Because of this, we had to completely rethink our approach to safety priorities. In practice, there was only one course open to us - we had to achieve much closer cooperation with all the teams.

"For each race, first the teams supplied us with data on the force that had been applied to the tyres in their simulations and with the actual data measured during the race. By comparing these data we could verify the performance of the tyres."

The performance we are talking about here is mainly durability. Tyres might have to run 100 km, 200 km or 300 km - in each case we would estimate beforehand how the tyre would perform, and after the race we'd check whether we had been correct or not. If we found before a race that the tyre might not be durable enough, due to the characteristics of that particular course or an individual driver's driving style, then we would actively go to the teams and propose different ways to use the tyres.

Since we at Bridgestone always placed first priority on ensuring safety, we told the FIA that we might have to ask for the racing distance per tyre to be shortened.

"For example, teams had the right to choose a strategy that used one specification for a long distance and the second for only a short distance. That meant we had to ensure the tyres could be used safely even under such an extreme strategy. This was an issue that concerned us from 2009 on. Before each race, we would go to the teams and tell them that our simulations for this course, plus the data from their cars, showed us that certain approaches would be dangerous. For example, we would warn them not to exceed a certain amount of negative camber, or not to use tyres inflated above a certain pressure."

Simulation accuracy had increased and so had the accuracy of the data showing their results from using those simulations on the track. Because we could no longer test during the season, it became extremely important to constantly verify simulated data with data taken at each race, in order to reflect this in the tyres we were preparing for the following race.

With no in-season tests, drivers play a new role

With the prohibition on in-season testing, the focus had turned to simulation technology. However, in the end it is always going to be humans who use the data, not computers. That's why we needed direct impressions from the drivers, gained on the track, to give a sense of reality to the simulation results.

"The drivers were certainly a major factor. During every race, a huge amount of data covering many categories is gathered from each car. That would include such items as loading, how much lateral G force was produced, and so on. However, just the data alone is not enough. We needed to flesh it out with something more - the driver's impressions as he handled the car. For example, a driver might report 'Coming out of Corner 2, I felt really strong lateral G, just as the data forecast.' So we would focus on that point. A driver's actual impressions were the best way to verify the accuracy of simulator results. It was also important for us to know how much we could trust the driver's feelings. For us, a good driver was one who provided consistently accurate feedback."

Who did we consider to be good drivers? Hamashima points to Michael Schumacher, champion five consecutive times. Fernando Alonso, the man who finally took the title away from Schumacher. And Sebastian Vettel, in 2010 the race's youngest ever champion.

"A number of things made these drivers outstandingly useful from our standpoint. If they don't know something, they won't hesitate to admit it. When they feel something through their body when driving, they can pinpoint the cause - whether it's a change in the road surface, something different in the car, or something new about the tyres. And most important, these drivers have the ability to explain what they feel clearly and precisely."

Brawn GP dominates season despite top teams' comeback

Unlike most years, the 2009 season wasn't dominated by veteran rivals McLaren and Ferrari. Instead, all eyes were on the progress of a team making its Formula One debut - Brawn GP.

The new team was led by Ross Brawn. As Ferrari Technical Director, Brawn - along with Michael Schumacher and Jean Todt - had been a major player in Ferrari's F1 golden years from the late 1990s to 2006. After Schumacher retired, Brawn began a long sabbatical, but then came back to F1 during the 2007 off season to run the Honda team. When Honda decided that 2008 would be their last F1 season, Brawn led a management buyout of the Honda team and quickly prepared to enter it for 2009. It took time to put the team organisation together, and they weren't ready to take part in testing until March, close to the season's opening race. In the tests the Brawn cars consistently set excellent times, and Hamashima remembers thinking that they must have been running underweight.

However, once the season started, the Brawn cars showed that this speed advantage was real as Jenson Button drove his Brawn to first place in six of 2009's first seven races.

"The Brawn GP cars originally had a tendency to understeer. In fact, after the end of the previous season, these (then Honda) F1 cars had been tried out on slick tyres at the Twin Ring Motegi circuit. That was when Jenson Button started feeling good about their performance. The oversteer caused by using slick tyres turned out to perfectly balance the inherent understeer of this car's design."

Brawn GP were also helped by fitting double-decker diffusers before most other teams, and they had been given a big advantage by the prohibition of in-season testing.

The other teams, of course, didn't simply sit back and watch as Brawn raced ahead. Hamashima: "Now there were no tests allowed, everyone was carefully watching each race to see which team regained its edge first." It would be McLaren. "They were the ones who had taken the regulation changes to heart and built a strong new development system based on computer simulations."

"McLaren used a trial and error system with repeated indoor tests always being carefully verified using real cars. As the season progressed, this began to show results. McLaren could be seen bringing newly developed parts to each race that effectively matched the characteristics of that circuit. It was McLaren who first really established this methodology."

The computer simulations always gave a definite response. Even a change in input values as small as 0.5 would produce a different result. And this could be done in reverse to find the values needed to achieve the ideal response. However, testing those responses on the actual circuit was a rather different story. You needed a highly accurate development system in order to combine simulated and measured data to find the path to victory. And only the top teams could invest the time and money required for this.
This was the reason why first McLaren, then Ferrari and Red Bull, made such a comeback in the second half of the season. But because no-one had been able to challenge the Brawn cars in the first half, the combination of their six early wins with points accumulated later gave Button the Drivers' Championship, with Brawn GP talking the Constructors' title.

At season's end, a sad decision by Bridgestone

The global financial crisis triggered by the failure of Lehman Brothers in September 2008 would also have repercussions on the world of Formula One racing. At the end of 2008, Honda announced their retirement, and in July 2009, BMW followed suit. And, sadly, Bridgestone would not prove immune to this trend.

On November second, directly after the close of the 2009 season, Bridgestone made it official. We would not be renewing our contract with the FIA when it expired at the end of 2010.

The reason given was that the company wanted to reallocate management resources to focus future investment on developing innovative technologies.

Just two days after Bridgestone's announcement, Toyota unexpectedly broke the news that they too would be leaving Formula One.
Honda. Toyota. Bridgestone. One by one, Japan's major corporations were withdrawing from F1 racing.