Denny Hamlin was fastest in Friday afternoon’s first of two Xfinity Series practices at Darlington Raceway.
Hamlin was one of three drivers that surpassed 170 mph, topping the 41 cars that took to the track with a speed of 170.608 mph.
Tyler Reddick was second at 170.306 mph, followed by Justin Allgaier (170.083), Elliott Sadler (169.485) and William Byron (169.479).
Sixth through 10th were Cole Custer (168.885), Brennan Poole (168.781), Joey Logano (168.700), Ben Kennedy (168.457) and Erik Jones (167.762).
The second and final Xfinity practice runs from 2:30 p.m. - 3:25 p.m. ET today.