There was not much news coming from from the three-day test before Rosberg used twitter to give his insight.
"Just spun at full speed 320km/h on bahrain straight cause my tyre blew up without warning. Thanks to that need to get some toilet paper now," he wrote before the tweet was swiftly deleted.
Mercedes used Rosberg for the entire test which also saw the participation from Ferrari, Red Bull and Toro Rosso.
Pirelli organised the test to develop their 2014 tyres with the drivers running the 2013 cars.