The first of two Camping World Truck Series practice sessions at Chicagoland Speedway was led by John Wes Townley.
Townley put down a top speed of 175.182 mph and was the only driver to top 175 mph in the 55-minute session.
Matt Tifft, who will make his first NASCAR start since undergoing brain surgery for low-grade tumor on July 1, was sixth fastest at 173.332 mph.
John Hunter Nemechek was 19th fastest at 171.876 mph.
The second Truck practice will run from 6:30 – 7:25 p.m. ET.