Translated from Italian via Google:

The decision to use 17 inche Michelin tires  when they return to MotoGP as the sole supplier in 2016 was ratified by the Grand Prix Commission. At Barcelona, in fact, was approved a regulatory change to allow the approval of the bikes with wheels larger image from next year, a necessary condition for testing the new tires.

Read more: http://www.gpone.com/2014061613931/UFFICIALE-Michelin-sceglie-gomme-da-17.html#ixzz34oJg6ONv