The final four days of practice before the second season of Pirelli’s Formula One tyre supply tenure begin tomorrow in Barcelona. The tyre manufacturer believes the session will be one of the most crucial tests of the season, with teams seeking to gain the best understanding possible of how the P Zero and Cinturato tyres work with their new cars before racing begins in Australia. In the long-term, Pirelli says that non-stop development means that the cars will change considerably as the season goes on. Additionally, an intriguing aspect of practice is the way teams will want not to show their full potential, and the desire not to tip their hands while finding the true potential of their cars on the new rubber is a key aspect of reading test times. Eight different drivers have recorded fastest times during the eight days of testing in Jerez and Barcelona underlining how difficult it can be to draw concrete conclusions.