Only good fortune prevented the wheel upright, which included the tire, hub, wheel bearing and brake assembly, from landing in the crowded grandstands, with the only damage being delivered to a passenger car in a parking.
After extensive analysis by Dallara and IndyCar, it has been determined that the triple wheel tether system did not fail, but rather the retaining nut on the inside of the wheel hub itself.
A redesigned wheel nut, which is 60% stronger than the original variation, has been distributed by Dallara for immediate use by the entire paddock.
“Dallara continues to be a tremendous partner of the NTT IndyCar Series,” IndyCar President Jay Frye said.
“Their thorough review process of the incident between the No. 6 and the No. 27 at Indianapolis Motor Speedway began immediately and included an extensive recreation at their headquarters in Italy.
“IndyCar takes safety very seriously. This update is an important step in making sure an incident like this does not happen again.”
Use of the new retaining nut will be mandatory for all teams beginning this weekend at Iowa Speedway, which is hosting a double-header event.
It is not believed that this particular component has failed at any time other than the incident in question this past May, but IndyCar and Dallara went to great lengths to make sure that it is the only such occurrence.
“It is Dallara’s mission, along with IndyCar and all of the racing series we work with, to maintain and continuously improve safety based upon the highest standards,” Dallara CEO Stefano dePonti said.
“After completing a detailed analysis of the accident during this year’s Indy 500, together with IndyCar we have reached the conclusion that the outcome was the consequence of an unusual and never experienced set of circumstances.
“Nevertheless, we have developed and produced new components that will increase the strength of the corner in case the unlikely sequence of events repeats itself.”