The new rule will go into effect next week when the Chase for the Sprint Cup begins at Chicagoland Speedway. The new rule places parameters on the truck arm front mounting bushings, which will be allowed to only have a maximum of a quarter-inch in total movement in one direction.
The bushings — pieces of rubber or other material near the mounting points — must be designed to move freely and not lock in one position.
Teams have been using softer bushings to allow the truck arms to move more and give the driver more rear steer through the turns.
The bushings are the area that Brad Keselowski referenced recently when he said that the Hendrick teams had exposed a gray area in the rulebook, gaining an aerodynamic advantage. NASCAR officials concluded that the Hendrick teams and others using more rear steer had not violated any rules.
"When we presented it to NASCAR for approval, they didn't act like it was something they had never seen before," Hendrick driver and four-time champion Jeff Gordon said. "I don't even think we were the first ones to do it."
Gordon also alleged most everyone in the garage is doing the same thing now, which Kyle Busch confirmed — with a caveat.
"We all started working on it once we saw what they were doing," Busch said. "It's follow the leader. You really don't have many secrets here in the garage area very long. We started going to work on those kind of things, too, and trying to manipulate some of the same things they were doing."
Sprint Cup Series Director John Darby said two weeks ago that he had a bucket full of bushings that teams had brought to NASCAR for approval.
He said then that NASCAR would only react if it believed things were getting out of hand with the use rear steer.
“We try to manage rule changes and keep them to a minimum at this time of year because of everything — the guys that are trying to get in the Chase, the guys trying to make races, the whole program," Darby said Aug. 24.
While admitting the bushings provided an advantage, "it's a legal advantage," Busch said. "There is nothing illegal with what they were doing." Sporting News