Austin Cindric was fastest in an eventful NASCAR Cup series practice session at Dover Motor Speedway.
Cindric, from Group A, laid down the fastest overall lap at 157.846 mph (22.807 seconds). AJ Allmendinger was second fastest at 157.805 mph, with Kaulig Racing teammate Justin Haley third fastest at 157.694 mph.
Denny Hamlin was fourth fastest at 157.591 mph, and Kurt Busch was fifth at 157.508 mph.
The rest of the top-10 in practice was Ryan Preece in sixth (157.46 mph), Brad Keselowski seventh (157.453 mph), Ryan Blaney eighth (157.418 mph), Chase Elliott ninth (157.350 mph), and Christopher Bell 10th (156.993 mph).
Defending race winner Alex Bowman was 17th fastest at 156.427 mph.
Five drivers encountered trouble in practice.
William Byron got loose going into Turn 3, going up the banking and hitting the wall with the right side. The contact severely damaged the right side of the No.24 Chevrolet, and Byron will go to a backup car for Sunday’s race.
“I got through (Turns) 1 and 2 really good, actually, and think just a little overconfident getting into (Turn) 3,” said Byron. “I know our backup car can be just as fast (as the primary), and we can go try to win on Sunday.”
Behind Byron’s crash, Tyler Reddick spun in a reaction to the caution coming out. Byron nicked the wall with the rear of his Chevrolet, but it did not appear to be significant contact. However, Reddick then bounced off the wall off Turn 2 with the right side of his car.
After the Byron red flag, Wood Brothers Racing rookie Harrison Burton spun in Turn 3 and bounced off the wall.
“I got through (Turns) 1 and 2 really good on that lap and felt pretty confident going to (Turns) 3 and 4 that I could go get some extra speed and be aggressive there,” said Burton. “As soon as I turned into the corner there I just lost the back of the car. I don’t know, it just snapped around really quick.”
Fornt Row Motorsports rookie Todd Gilliland spun in the opening moments of the session in Turn 3 and bounced the left rear of his Ford Mustang off the wall.
Shortly after the red flag was lifted for Gilliland’s spin, Josh Bilicki crashed off Turn 2. Bilicki got loose off the corner and hit the inside wall with the No.77 from Spire Motorsports, suffering significant damage to the car’s front nose and right rear.