Tyres strategy is one of the biggest challenges for teams during the Formula One season.
However, there are many variables and considerations which have to be taken into account by the supplier before the tyres screech onto the track, according to Hirohide Hamashima, director of motorsport tyres development for Bridgestone.
To begin with Bridgestone considers many factors when looking to determine its tyre allocation for each Grand Prix.
Hamashima said: “There are many variables involved, these are variables such as the weather and the track surface which we can only predict, but not be certain what is going to happen.”
In contrast to a competitive tyre supply environment, where more than one manufacturer is involved, Bridgestone does not make different tyres for each circuit or team.
“In times of no (supplier) competition we have worked closely with the FIA and we now only produce four different specifications of dry weather tyres to cover the whole season,” explains Hamashima.
“This means that each tyre has to have a wider working range than before, so it can be used by a variety of different cars and at a variety of different circuits.”
An additional challenge is provided by the regulations necessitating the use of two different tyre types during the course of each Grand Prix.
“This provides a challenge for Bridgestone as well as the competitors,” points out Hamashima. “When we started with this concept at the beginning of the 2007 season we could see that the lap time difference between the two tyres was quite big, and it was interesting to watch the teams and drivers develop their knowledge and ability of how to best use the two tyres.”
The weather, as everyone has seen so far in the 2009 season, can be a large influencing factor. And it’s not just if the weather is wet or dry that matters, hot or cold environments makes a big difference as well.
“The temperature can certainly change the tyre focus for teams over the course of a race weekend,” explains Hamashima. “As an extreme example, an unexpectedly hot track could mean that the harder tyre for a race weekend is actually better for qualifying than the softer one, which would usually be the better one.”
“In contrast, an unexpectedly cold track could mean that the softer tyre becomes the better race tyre,” he adds. “So there is a lot to consider for tyre selection over the course of the race meeting.”
The track surface also provides an interesting variable, and aspects of this are related to the weather too.
“The general trend for race weekends is for the track surface grip to improve as rubber from our tyres is left on the track, providing a good high grip surface,” Hamashima elaborates.
“However, how dirty or clean the track is on the first day makes a difference, and that can depend on how many recent race meetings there have been at the track as well as how much rain there has been before the race meeting, or even how hot and sunny it has been.”