Justin Marks claimed the fastest speed in the first of two Xfinity Series practice sessions Saturday at Road America in Elkhart Lake, Wisconsin.
Marks covered the 4.048, 14-turn road course with a top speed of 107.923 mph.
Brennan Poole was second (107.846 mph), followed by Austin Cindric (107.479), Justin Allgaier (107.312) and Brendan Gaughan (107.266).
Sixth through 10th were Blake Koch (107.092), Matt Tifft (107.048), Cole Custer (106.899), Dylan Lupton (106.781) and Jeremy Clements (106.599).
Christopher Bell, driving the No. 18 Toyota for Kyle Busch Motorsports, suffered transmission failure, prompting his team to replace it. He managed just one lap of practice before he took the car to the garage.
Bell is expected to be ready for today’s second practice at 4 to 4:55 p.m. ET.