RICHMOND, Va. — NASCAR views the technical bulletin issued to Cup teams this week as reaffirming existing rules regarding setup of the rear suspensions, but it does limit the amount of finagling crew chiefs can do with the truck trailing arm front mounting bushing assemblies.
If that techno-speak seems hopelessly arcane, NASCAR is making sure crew chiefs understand the limits, direction and freedom of “travel” or movement in the rear suspension that’s allowed under existing rules.
The bottom line is that rear-axle steering improves the aerodynamic properties of the Cup cars and allows them to turn more easily through the corners. The bulletin specifies a quarter-inch of travel in one direction only, and the assemblies in question must move freely through that quarter-inch of travel (as opposed to locking in position, for example).
With Hendrick Motorsports at the vanguard, Cup teams have been working hard to maximize the aerodynamic advantages of rear suspension setups.
“This doesn’t change any rules that we’ve already had,” said Cup series director 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.”
Five-time champion Jimmie Johnson didn’t appear concerned about the bulletin.
“I think NASCAR made it known that they are just putting parameters on what’s going on,” Johnson said. “There is no change.”