The Michigan firm is responsible for the hugely successful aero kit used by motorsport partner Chevrolet, and it was understood there was widespread support across the paddock for the company to design the package that will end a three-year aero war between Chevy and Honda. However, Mark Kent, director of competition for Chevrolet and Cadillac, told RACER that Pratt & Miller has elected not to be involved due to tight time frames and uncertainty over the design parameters.
"The question was posed by IndyCar as to whether [Pratt & Miller] would be interested, but Pratt & Miller elected not to pursue that," he said.
"I believe that their concern was just with the amount of time allowed between now and 2018, and the unclear scope of what needed to be accomplished. They weren't prepared to put their reputation on the line without fully understanding what they were signing up for. So I believe they have elected not to participate in the development.
"We've seen some of the  concepts, but the devil is in the detail. There are some high-level concepts, and there are some good initiatives with safety, which we are fully supportive of. But without knowing the details it would be a challenge to get there by 2018."
Any Pratt & Miller involvement in the 2018 aero would have required Chevrolet's approval due to the exclusive motorsports agreement that exists between the two entities. Chevrolet will formally claim its fifth consecutive IndyCar manufacturers' championship at Sonoma tomorrow. Mark Glendenning/Racer.com