Away from the groove - Bridgestone on the return of slicks 05 May 2008
Formula One cars will line up on the grid for this weekends Turkish Grand Prix with Bridgestone Potenza grooved racing tyres on them, but for next years race the tyres could be very different.
Formula One has raced with grooved tyres since their introduction in 1998, but the regulations for the 2009 season feature a number of changes, including the removal of the stipulation that dry racing tyres must have longitudinal grooves along the tread area.
These grooves were designed to curb speeds through the tyre having a smaller contact patch with the road. Less contact means less grip and slower speeds through the corners, meaning slower lap times.
It is an interesting and significant development for Formula One to return to slick tyres, says Tetsuro Kobayashi, Bridgestone Motorsports technical manager. When we first saw the introduction of grooved tyres in Formula One we had a lot to learn. As a grooved tyre has a smaller contact patch with the road we needed to use harder compounds to attain the same levels of durability as we would see with a slick tyre of the same size.
Also, the grooves mean that the area that is in contact with the road is not as stable so more movement can take place in the rubber, which is something that has contributed to the greater amount of graining seen in the grooved tyres.
Bridgestone and the Formula One teams and drivers have worked with grooved tyres for over ten seasons now, so the change in the regulations for next year means a lot of work between now and the start of next season.
In recognition of the changes in the regulations we have made slick tyres available at two tests so far, says Kobayashi. The first was in Jerez where we brought one compound of slick Formula One tyre, and this was very much a prototype development tyre for ourselves and teams to gain initial data.
As well as the regulations no longer requiring grooves on the tyres, downforce levels will be significantly lower than before, and the use of tyre blankets which pre-heat the tyres to their operating temperature will no longer be allowed.
When we ran in Jerez, tests were undertaken with drivers taking to the track without the benefit of tyres pre-heated by blankets and this was a new situation for them in F1, says Kobayashi. Bridgestone collected a lot of data from that test and we applied it when developing the tyres for use in the recent test at Barcelona.
The latest test at Barcelona took place over four days, from April14-17, and teams were supplied with two compounds of the current 2008 specification tyres, as well as three compounds of prototype slick tyres.
The Barcelona test was interesting and the situation of warm-up for the slick tyres was much improved compared to Jerez, says Kobayashi. Each team was issued with nine sets of slick tyres and we saw running take place with a variety of different car configurations.
With teams focusing on the 2008 championship and the following weeks race, the tests with the slick tyres took place with cars running to the 2008 regulations, as well as adapted to next seasons levels of downforce.
Formula One teams have been designing cars to work with grooved dry racing tyres for a long time, so the information that teams previously held on running with slick tyres was out of date, says Kobayashi.Although the 2008 cars have not been designed to run with slick tyres it was a useful fact-finding mission in Barcelona, building on the data we gained at the end of last season. This is part of the ongoing process to prepare teams for slick racing tyres returning to Formula One.
Bridgestone itself has plenty of up to date experience with slick racing tyres as it produces slicks for many racing categories including karting, Formula Three, Formula Nippon, Japanese GT, GP2 Series and the IndyCar Series. So if slick tyres were banned from Formula One with the aim of slowing down cornering speeds, surely the re-introduction of slicks will mean the cars will go faster?
The 2009 regulations as they currently stand incorporate a number of elements to slow the cars down, most notably cutting the downforce levels significantly, explains Kobayashi. Also, the banning of tyre blankets means that drivers will certainly have to be more circumspect as they leave the pits and this will be another area of tyre management where drivers will have to be vigilant.
On Bridgestones side we have changed the compounds to enable a lower temperature range for the tyres so that it is easier for drivers to get the tyres to their operating temperature quicker, and this is an area we will continue to work on.
Slick tyres are next scheduled to make a Formula One appearance in the Jerez test in July where two compounds will be used.
We have plenty of data from this latest test and this includes all the driver comments given to our tyre engineers, says Kobayashi. We will now analyse the latest data which will assist us in developing the tyres further.