
Drivers spent the session either scrubbing sets of tires or testing how long their tires last on the abrasive WeatherTech Raceway Laguna Seca. Pato O’Ward saw a drop off of around 2.5 seconds running a dozen laps on the Firestone alternates on his Arrow McLaren SP-Chevrolet, Rinus VeeKay saw seven second fall-off in his Ed Carpenter Racing-Chevrolet over 18 laps also on the softer rubber.
On alternate tires, Alex Palou ahead of probably his final event for Chip Ganassi Racing-Honda, set a best time of 1min12.9318sec. The outgoing champion will be starting the race from 11th, having received a six-place grid drop due to an early change to a fifth Honda.