NASCAR Sprint Cup Series drivers say they will face uncertain track conditions in today's Chase race at Phoenix as the evolving new surface and weather conditions have turned it into a 'moving target'.
The new asphalt at the one-mile D-shaped oval has proven extremely sensitive to conditions, as shown by Saturday's noon qualifying session when lap times were around a second slower relative to Friday's practice sessions, held under cooler temperatures.
A $15million (USD) reconfiguration and resurfacing project at the track took place ahead of the penultimate race of the season, with the Cup field testing for two days last month to get a grip on the increased banking and smoother asphalt.
Although grip levels have been picking up with more running, the track still has a narrow second groove on the outside, which is expected to make it hard to race side-by-side and overtake, as seen during Saturday's NAACAR Nationwide and K&N races.
Overnight and morning rain at Phoenix could further alter track conditions ahead of today's race, which is set to be key in the title fight.
"The biggest keys to this race are going to be, I think, you start with qualifying and then after that it is pitstops and restart strategy," said polesitter Matt Kenseth. "The tyres don't fall off at all. They don't really drop off in speed at all.
"It is going to be who can figure out how to keep their car up front. Who can be in the bottom on restarts and get good restarts and take advantage of the restarts when someone is in a bad position. I think that is going to be a big deal."
In an effort to get the track rubbered in on a second groove, six stock cars ran with soft tyre compounds early this week, completing approximately 3,000 miles between them. Additionally, a machine dragged more than 80 tyres on that second grove in order to rubber it in and enhance grip on the new asphalt.
Following Saturday's Nationwide Series race, Chase leader Carl Edwards said that he was able to race side-by-side despite the outside groove still being narrow, but it remains a challenge to complete a pass unless a rival makes a mistake.
"It is a pretty narrow two grooves and aero is a big enough factor here that guys can get loose if you are under someone and the track is a little treacherous," said Edwards.
"It is hard to pass. I think what I was saying about the difficulty in passing was that once you line up and you get in a line, if the guy in front of you is running the same groove as you it is a little tough when you are so aero dependant here and everyone is so closely matched to run him down and work him over. You need him to struggle a little bit."
The winners of both NASCAR races on Saturday at Phoenix came from the top five on the grid, Sam Hornish winning from fifth in the Nationwide Series and Ryan Blaney taking victory in the K&N West race in the evening.