A new color is coming to the sidewalls of Firestone Racing’s NTT IndyCar Series tire. Unveiled on Friday at the Indianapolis Motor Speedway as part of a wide-raging Earth Day presentation, Firestone’s parent company Bridgestone Americas announced the introduction of a green-banded tire that makes use of an eco-friendlier rubber that shifts harvesting from trees to the robust guayule shrub grown in the U.S. Southwest.

The new green Firestones will be put to use for the first time during the Indy 500 Pit Stop Competition in May and return in August as the alternate compound at the Big Machine Music City Grand Prix street race in Nashville.

“Bridgestone has committed to carbon neutrality and 100-percent new renewable materials by 2050,” Cara Krystolic (formerly Adams), the director of race tire engineering and manufacturing, and chief motorsports engineer for Bridgestone Americas, told RACER. “We have a new E8 commitment where we talk about emotion, ecology, energy, and sustainability is the key here.”

The new green guayule rubber is no different from the rubber harvested from the hevea brasiliensis rubber tree in terms of grip or degradation. The key change is in the manufacturing resources required to produce the two types of rubber, with guayule needing a significantly reduced amount of water during its growth and maturation process.

“The guayule shrub is not susceptible to some of the disease threats or climate change threats that we have with the natural rubber tree,” Krystolic adds. “It’s an alternative natural rubber where the natural rubber that can be very drought resistant and heat tolerant.”

Domestically grown guayule shrubs.

Along with the new tires for the Pit Stop Competition, all of Firestone’s Indy 500 tires will be transported to the Brickyard in electric tractor-trailers to further support the company’s commitment to sustainability.

“The introduction of guayule natural rubber to America’s pre-eminent open-wheel racing series speaks to the confidence we have in the technology and its promise as a scalable, sustainable and domestic source of our industry’s most vital raw material,” said Nizar Trigui, CTO and group president for solutions businesses at Bridgestone Americas. “It will take partnership and collaboration to combat the impacts of global climate change and we are proud to partner with Penske, IndyCar and IMS to advance the future of sustainable mobility.”