IndyCar will reduce downforce in the cars for the race at Iowa Speedway on Saturday night.
The decision was announced Monday and will reduce downforce by about 9 percent.
IndyCar vice president of technology Will Phillips says reducing the downforce makes the cars difficult to drive, and most of the drivers have been asking for that challenge. The drivers unanimously voted for less downforce two weeks ago at Texas to eliminate the pack racing that develops on high-banked ovals.
Aside from the reduction of downforce and removal of the rear wicker, IndyCar will use the same short oval aerodynamic package it used last weekend at Milwaukee.
IndyCar also said it will set the fields for Friday night's qualifying heat races by lap times recorded in the second practice session.