The right side rear deflector fins, added to NASCAR Cup Series cars this past weekend at Daytona in the aftermath of Corey Lajoie flipping at Michigan International Speedway the week before has now been made officially part of the rule book.
The air deflector, which is identical to the one already on the left side of the car, is now mandated for all tracks designated as intermediate and superspeedway tracks.
The rule goes into affect, not this weekend at Darlington, but the week afterwards at Atlanta Motor Speedway.
The Cup Series rule book has also been updated to feature CAD files and renderings of how it fits within the NextGen car holistically.
The right side fin made its debut at Daytona this past weekend and drivers said it made little difference to balance and handling of the cars.
There were also two other flips in the race, Michael McDowell blowing over on his side before landing on all four tires, and Josh Berry, who flipped completely and hit the backstretch wall while still upside down.