NASCAR Sprint Cup Series teams will be on the track a day earlier than normal when the series returns to Las Vegas Motor Speedway for Sunday's Kobalt 400.
A day-long test session scheduled for Thursday at the 1.5-mile track will provide teams with a total of six hours of on-track opportunity. The first session is scheduled to run from noon until 2 p.m. ET, followed by another three-hour window from 3-6 p.m. ET.
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The additional track time was built into this weekend's schedule to allow teams to continue working with the new 2016 base rules package, a low-downforce configuration that features a shorter spoiler (3.5 inches) as well as changes to the front splitter (an 0.25 leading edge) and radiator pan (33 inches wide).
The package, similar to one run at Kentucky Speedway and Darlington Raceway last season, debuted last weekend at Atlanta Motor Speedway.
Goodyear tested with four drivers -- Jimmie Johnson (Hendrick Motorsports Chevrolet), Kurt Busch (Stewart-Haas Racing Chevrolet), Matt Kenseth (Joe Gibbs Racing Toyota) and Brad Keselowski (Team Penske Ford) -- Jan. 12-13 at LVMS to confirm the tire choice for this weekend's race.
Teams will be provided with an additional six sets of tires for Thursday's test. It will be the first time Sprint Cup teams have run the two tire codes at Las Vegas. According to Goodyear, the right-side tire is a multi-zone configuration, featuring two different tread compounds: The inside two inches of tread built for endurance and heat resistance, while the outer 10 inches built for traction.
The left-side tire build features a compound change in an effort to provide more grip.
Drivers gave the rules package high marks following the Atlanta race, although many expect tracks such as Las Vegas, which features a surface that isn't as fast or as worn, will provide a better indication of what to expect from the changes.
"Because Las Vegas has a lot of grip," Kenseth said, "it's really fast and there's always really bad aerodynamic effects as you get further back in the pack. The reason that you have a tough time passing at Vegas is because of the aero, so I … think this weekend will be a good base for looking at this new package."
Sprint Cup teams will be provided five sets of tires for practice at Las Vegas and nine sets for Sunday's race.
Kevin Harvick, the 2014 series champion, is the defending race winner.
As was the case at Atlanta, teams will have one practice on Friday, followed by qualifying, and two Saturday practices to prepare for Sunday's 267-lap race.