Firestone, which makes tires in Des Moines, tests technology during IndyCar races in Iowa

AI-assisted summary
• Firestone is incorporating soybean oil, sourced from Iowa, into its tire production, starting with IndyCar racing tires.
• Soybean oil is being used as a sustainable replacement for petroleum and other oils in tire sidewalls.
• Firestone uses racing as a testing ground for new tire technologies before implementing them in consumer tires.

NEWTON—Tires made in part with soybeans grown in Iowa will be coming soon to Firestone stores.

Firestone, IndyCar's tire manufacturer, tests tire technology by using it first in its IndyCar tires before making it more widely available in consumer tires. The company is owned by Bridgestone Americas, which employs 700 people at its Des Moines Agricultural Tire Plant. The plant also makes Firestone tires for tractors.

Cara Krstolic, Firestone race tire engineering and production executive director, said that Firestone's consumer tires — whether manufactured for cars or tractors — share some materials with its racing tires. In 2022, Firestone introduced an alternative tire made from guayule, a plant that grows in the southwestern U.S. and northern Mexico, to use on street courses. More recently, Firestone added soybean oil to its race tires.

Soybean oil is used in sidewalls of tires, and the company is experimenting with other uses for it, Krstolic said.

"Leftover residual oil from the soybean can be used to replace petroleum," Krstolic said. "And it can also work on reducing some of our other oils in the tires."

Soybeans are also more renewable than other plants Firestone has experimented with, she said.

"The nice thing about the soybean is that there's enough sources that you can get that (and) you're not competing as food source," Krstolic said. "

Among the products Firestone makes at Bridgestone's Des Moines factory are tractor tires, which sit on a tractor in Victory Lane.

Since its inception, car and tire manufacturers have used racing to test products before rolling sales out to consumers. Firestone founder Harvey Firestone coined the phrase, "Win on Sunday, sell on Monday."

Each race weekend Firestone brings about 20 people to mount tires and six engineers to monitor tire temperatures and other data on tires. Eventually all of this work at Iowa Speedway and IndyCar's 15 other tracks makes it into consumer tires, Krstolic said.

"Racing is a mobile lab," Krstolic said. "Where else can you see the extremes of heat and durability and performance than on race tracks?... So there are materials that we'll put into this race and other races that we can prove out at speeds of 200 mph."

Philip Joens covers retail, real estate and motorsports for the Des Moines Register. He can be reached at 515-284-8184 or pjoens@registermedia.com.