Found this article. Seems pretty odd with them being the only tire this year.

The 50th premier class win on Bridgestone tyres came after a head-to-head battle between the only two riders to have won a World Championship using Bridgestones.
It was inevitable given Bridgestone’s status - as of this year - as MotoGP’s sole tyre suppliers, but their 50th premier class victory is a landmark moment for the Japanese tyre firm and has come as a result of several seasons of hard work.

Victories over their competitors stretching back to 2004, when they got their first win with Makoto Tamada and Honda in Brazil, have led to Bridgestone’s position as the single supplier trusted with providing MotoGP’s teams with the highly competitive material which has produced such close and exciting racing this year.

When Casey Stoner triumphed over Valentino Rossi by less than two seconds after a race-long battle at Phillip Island on Sunday both riders were using the softer front and rear Bridgestone slicks as they pushed each other to within 0.03seconds of the circuit lap record, and mid-race the duo were separated by less than one tenth of a second.

There has been widespread praise for Bridgestone throughout the paddock this year and they are set to rack up the victories as their partnership with MotoGP continues.

Regarding the landmark, Hiroshi Yasukawa, Bridgestone Corporation’s Director, stated, “I’d like to congratulate Casey and the Ducati team for their victory in Australia and for marking the 50th win on our tyres. It is apt that Casey took this win as it was he who took the first World Championship on our tyres in 2007.”

“We are proud to have achieved this milestone, and whilst this is the first of three years for us as the Official Tyre Supplier, it is important to note that almost three quarters of these victories came in the tyre competition era, and that it was our success and the performance of our tyres that saw us become the sole supplier. I would like to express my sincere gratitude to Dorna and the FIM for their continued support, and wish each MotoGP team and rider the greatest success for the remainder of this season and beyond.”

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