NASCAR has issued a clarification of the limits of rear axle settings amid suggestions that Hendrick Motorsports has gained an edge over rivals with its rear-suspension setups.
The sanctioning body has informed Sprint Cup teams that starting next week with the Chase opener at Chicagoland, wheelbase, rear-axle location, offset and housing alignment will be inspected both before and after the race, having previously only been checked pre-race.
NASCAR has "reconfirmed" the limits set by the rulebook clarifying how much movement the bushings allow to the front mounting points of the trailing arm, thus setting limits to rear-axle steering. Officials have stated the bulletin does not change any existing parameters, but adjustments to further harness rear-axle settings could be made for the 2013 season.
"This doesn't change any rules that we've already had," said NASCAR's John Darby. "It reconfirms how far teams can go with their rear suspension setups.
"Teams have found that with a car's rear axle steer more is better as it helps with aero and gets the cars through the corners faster. We are just reminding the teams what the limitations are and that they cannot go past these limitations. We will likely address this further in our 2013 rule book."
Hendrick driver Jimmie Johnson says the technical bulletin is not aimed at his team. The team's cars, especially Johnson's, have appeared to run more visible "yaw" than rivals, making the car look sideways on the straights but helping corner turn-in. This also exposes the right corner of the rear spoiler to the air, therefore increasing downforce.
"I think NASCAR made it known that they are just putting parameters on what is going on," said Johnson. "There is no change. That is just what it is and what it has been. If there are rule changes we will adjust and do our best job.
"There has been a lot of discussion about it, but to add to the conversation a lot of people are focused and think that it is just Hendrick or big teams that have been working in this area. The field migrates quickly in certain directions and I think NASCAR is just making sure that people understand the parameters so that they can regulate in post-race and find ways to make sure no one is going above and beyond."