Following input from series drivers and team engineers, IndyCar has directed a maximum rear flap angle of 37 degrees with no wicker allowed for the Iowa Corn Indy 250 on June 23 at Iowa Speedway.
The technical bulletin sent to teams today follows two days of testing by 21 cars total at the .875-mile oval last week. IndyCar says the modification will reduce downforce available by about 8-9 percent.
"Like Texas, we want to make sure the challenge is in the drivers' hands and make them work each lap," said Will Phillips, IndyCar's vp of technology. "It will be more of a challenge for drivers once their tires start to go off (during the 250-lap race)."
Aside from this alteration, the short oval aerodynamic package utilized at the Milwaukee Mile this past weekend will be employed – mandatory speedway front brake backing plates, prohibit rear wheel infills and sidepod top deck, optional two-thirds radiator inlet shutters.
In a departure from single-car qualifications, three heat races will be held on Friday, June 22 to set the starting grid for the 250-lap race on Saturday.