INDYCAR, along with longtime partner Dallara, is providing an update to improve the overall strength and retention of wheel hubs on NTT INDYCAR SERIES cars.

The updated rear-wheel bearing retaining nut is being distributed to all entries in the NTT INDYCAR SERIES and will be mandated for use beginning at this weekend’s Hy-Vee INDYCAR Race Weekend doubleheader at Iowa Speedway. The strength of the rear-wheel bearing retaining nut has increased by 60 percent over the previous design.

Revisions to the existing component came after a meticulous review of the incident at the 2023 Indianapolis 500 presented by Gainbridge involving the No. 27 car of Andretti Autosport and the No. 6 car of Arrow McLaren, which resulted in the loss of the left rear wheel assembly on the No. 27.

“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.”

Previously, it was determined that the wheel tether system, using high-performance Zylon material, did not fail in the May 28 incident. INDYCAR was the first sanctioning body in the United States to require its use.

“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.”

The next race for the NTT INDYCAR SERIES is the Hy-Vee Homefront 250 presented by Instacart Saturday, July 22 at Iowa Speedway. Coverage begins at 3 p.m. ET on NBC with a simulstream available on Peacock. The doubleheader at “The Fastest Short Track on the Planet” continues Sunday, July 23 with the Hy-Vee One Step 250 presented by Gatorade. Coverage on Sunday begins at 2 p.m. ET on NBC and Peacock. The INDYCAR Radio Network will also provide coverage throughout the weekend.