Sam Laffins led the opening session of the last ever Junior Superstock round as he clocked a 1min 43.920sec lap as the rain continued.
In a session where just 14 riders hit the track, Asher Durham was the only one of the four title challengers to go out and ended the session second, some 2.077secs behind.
The session was stopped 30 seconds early after a crash involving Harrison Crosby and Jacob Hatch, both who walked away unhurt, with Crosby finishing third, Edmund Best fourth and Australia’s Hatch fifth.
Pirelli National Superstock with Santander Consumer Finance, free practice one result:
1. Sam Laffins (G&S Racing) 1min 43.920secs
2. Asher Durham (G&S Racing) +2.077s
3. Harrison Crosby (JR Performance Racing) +2.144s
4. Edmund Best (Symcirrus Motorsport) +2.473s
5. Jacob Hatch (Completely Motorbikes Kawasaki) +2.635s