As the first of the final back-to-back pair of overseas races of the 2011 season, the MotoGP paddock heads to Australia’s Phillip Island circuit for round 16 on Oct. 16, where mathematically there is the first chance for the 2011 title to be sealed.
Phillip Island is an unusual circuit in that it manages to be the least demanding venue on the 2011 MotoGP calendar for the front tires and the right shoulders of the rears, whilst at the same time the hardest of the year for the left side of the rears.
The weather at the coastal MotoGP track is often cold and windy in October, meaning that softer compounds are required to generate grip and good warm-up performance, and with only one area of heavy braking front tire stability is not so critical.
But the MotoGP circuit is fast and flowing, with the highest average speed of any circuit on the calendar, and the last two long left-handers are responsible for the highest rear tire temperatures of the season.
All of which requires Bridgestone to provide a special construction of rear slick tire designed to maximize warm-up MotoGP performance, particularly in the cold morning sessions, whilst also being able to cope with tire temperatures that can exceed 120 degrees Celsius.
The rear MotoGP tires Bridgestone have selected for Phillip Island have been improved since last year, in the form of construction and ability to cope with temperature, so consequently the available compounds are one step softer than in previous years.
Both options feature the extra soft compound rubber in their right shoulders for maximum warm-up and rider safety and confidence in the opening laps, and either the medium or hard rubber in the left side. These special construction tires have already been proved in action this year, at the almost-as-demanding Sachsenring MotoGP circuit.
As far as front tire compounds are concerned, they are the same as last year in soft and medium compound guise. Only two front tire options are available in Phillip Island, as opposed the three that have been offered since the Czech Republic Grand Prix, because the soft compound front slick is already selected for Australia MotoGP for its warm-up performance advantage so a third emergency spec for cold weather is not needed.
Hiroshi Yamada (Manager, Bridgestone Motorsport Department) says: "Casey enters the Australian Grand Prix with a 40 point lead over Jorge meaning that if he wins, which he has done here at his home track for the last four years in a row, he can clinch the World Championship if Jorge finishes fourth or lower so it is bound to be a tense but very exciting race weekend.
"Phillip Island is an unusual MotoGP circuit for us because of the disparity of the demands placed on the left and right shoulders of the rear tires, but I am confident in our tire offering this year, especially as we have chosen softer rear slicks for increased rider safety in an ongoing drive to provide the best possible warm-up performance."
Hirohide Hamashima (Assistant to Director, Motorsport Tire Development Division) says: "Despite being the highest speed circuit on the calendar with an average speed of over 180kmh, Phillip Island MotoGP is generally not tough on most sections of the front and rear tires because of the low ambient temperature and flowing nature that presents only one point of heavy braking in the lap.
"However the challenge comes from the last two corners in particular, as by stark contrast they generate the highest rear tire temperatures of the year in the left shoulders. The two corners are long and fast and generate high lateral loads and thus temperature and the stresses demand a special construction of asymmetric rear tire in order to cope without blistering.
"We have seen in the past that the cold and rain can be important factors so we have selected softer compounds of rear slick tyre this year, the same as we made available in Germany earlier in the year. Using a special construction, the rear tires we have selected are able to cope with such temperature whilst the softer options will maximize warm-up performance and rider safety in the early laps of each session which is important."
Bridgestone slick compounds available: Front: Soft, Medium. Rear (asymmetric): Medium, Hard