Pirelli first returned to F1 in 2011 under an exclusive contract that saw it replacing Bridgestone as the sole tire supplier to the series – a role it has held ever since. With Pirelli's contract coming up for renewal after next season, Michelin threw its hat into the ring. However Pirelli apparently did what it took to secure the contract for another three seasons.
The question still on the table is whether Pirelli will essentially continue with the same basic specifications, or make a radical shift in cooperation with the teams and organizers of the racing series. Both Pirelli and Michelin have proposed switching from the current design – which combines 13-inch wheels with high-profile sidewalls – to larger wheels with lower-profile tires.
Pirelli has also drawn much ire from the participating drivers and teams over the compounds developed by the tire manufacturer, which have been designed to last longer but provide less grip. The particulars of the deal, however, will likely remain known by only a select few at the FIA, Pirelli, and Bernie Ecclestone's Formula One Management company until they're good and ready to disclose them to the rest of us.