According to Nick Chester - Renault:
"
The deltas between the tyre compounds aren’t quite as expected here –
there’s not much between them"
Then, Mario Isola, head of F1 and Car Racing
"
The remarkable thing about today’s session was the fact that Lewis Hamilton set his fastest time on the medium tyre, as opposed to everyone else who set their best time on the softs, as is usual for a Friday. This means that
there’s a strong chance of seeing these medium tyres in Q2, with some drivers perhaps using them to start the race on. There was a high degree of track evolution, with the circuit being very slippery this morning. This caused the cars to slide a lot, as a result of which we saw some graining. In warmer temperatures and with more rubber on the track, this phenomenon was progressively reduced, to the extent that the fastest FP2 time was more than 1.5 seconds quicker than last year. We anticipate seeing the lap times get even quicker tomorrow, as they have done throughout the season to date."
courtesy of F1.com :
https://www.formula1.com/en/latest/arti ... 8Rh7R.html