The prospective 2017 aerodynamic rules package for NASCAR's premier series will receive what likely will be its final dress rehearsal this weekend at Michigan International Speedway.
NASCAR officials announced the move July 28, one month ahead of Sunday's Pure Michigan 400 (2 p.m. ET, NBCSN, MRN, SiriusXM). The 400-mile race is expected to be the last step before NASCAR's competition department delivers final, formal aero rules to teams as preparations for next season begin.
The rules at the 2-mile track this weekend will be a repeat of what the series competed with earlier this year in a 400-mile event won by Joey Logano. The rules are designed to reduce the over-stabilizing effects of downforce and sideforce with smaller spoilers, fewer cooling fans, and a neutral body alignment that eliminates rear axle offset, or "skew."
The Sprint Cup Series began the season with a five-stage process for testing and validating the potential 2017 rules setup. With last month's announcement, there's an unexpected sixth stage, intended to help competition officials accumulate more data and feedback before finalizing the package.
Similar incarnations of the package went through testing at Michigan (May 17) and Kentucky Speedway (June 13-14) before being used in race conditions at the NASCAR Sprint All-Star Race at Charlotte Motor Speedway (May 21), Michigan (June 12) and Kentucky (July 9). Competition officials have indicated they do not intend to adjust aero rules for any of the 10 races in the Chase for the NASCAR Sprint Cup playoffs, which begin Sept. 18 at Chicagoland Speedway.
The reduction of downforce and other aerodynamic stability has been an evolving philosophy during the last two seasons. The guiding principles behind the trends involve placing more control and input into the drivers' hands, and promoting side-by-side racing by minimizing the advantages of undisturbed, "clean" air for leading cars.
Last weekend at Bristol Motor Speedway, several drivers mentioned their desire for further testing of the package at more varied tracks before the 2017 rules are decided. Carl Edwards, winner of the series' two most recent Coors Light Pole Awards, still said he was encouraged by the push toward lower downforce, saying, "I think that the less we have, the better."
"Michigan is a tough place because even though we're reducing downforce, there is still a lot of it, but it's a very high-speed track so any aero changes, they are magnified there," Edwards added. "Hopefully the track has aged some there. It's a little hotter the second time back and there's a little more rubber down, and hopefully it provides a really good race.
"I hope it's a good test of that package. You test it at a new repave like Kentucky and you test it at a really, really fast single-groove track right now like Michigan and it's really hard to gauge where it's at, but I really applaud NASCAR trying and going that direction. I think what you've seen this year with all the great racing and the passing and all that is due in large part to the reduced downforce. If we can keep going that way, it's going to be good."