Jonathan Rea (Kawasaki Racing Team) was second quickest thanks to a 1’23.436 lap in FP2, with Marco Melandri (Aruba.it Racing - Ducati) third on the combined timesheets - with his best time (1’23.778) coming in the afternoon session.
It was a strong showing from Davies on his return to action, after thumb and back injuries sustained at Misano, which had kept him out of Race 2 at the last round.
Milwaukee Aprilia’s Eugene Laverty showed good pace to lap fourth best, his fastest time also coming from FP1, like that of Davies.
In fifth place was Tom Sykes (Kawasaki Racing Team), just ahead of Xavi Fores (BARNI Racing Team). Rounding out the top ten and therefore going straight into Tissot Superpole 2 at Mazda Raceway Laguna Seca were Leon Camier (MV Agusta Reparto Corse), Alex Lowes (Pata Yamaha Official WorldSBK Team), Jordi Torres (Althea BMW Racing Team) and Alex De Angelis (Pedercini Racing SC-Project).
The red flag came out early in the FP2 session after a crash for Stefan Bradl (Red Bull Honda World Superbike Team) at the top of the Corkscrew, whilst there were also crashes for Laverty, Lowes, Torres and Raffaele de Rosa (Althea BMW Racing Team) in the afternoon run.
Earlier in the day Davies’ rapid FP1 time saw him lead that session by a significant +0.673s margin ahead of second best rider Laverty, with Melandri in third place.
The action at the eighth round of the 2017 MOTUL FIM Superbike World Championship continues on Saturday with FP3 at 9.15am local time, SP1 at 11am, SP2 at 11.25am and Race 1 at 2pm.
#USWorldSBK Fastest on Friday:
1. Chaz Davies Aruba.it Racing - Ducati 1.23.425
2. Jonathan Rea Kawasaki Racing Team +0.011
3. Marco Melandri Aruba.it Racing - Ducati +0.353