February 8, 2025

Tires are one of the most environmentally problematic parts of any vehicle.

Indy Pit Stop Challenge - Guayule
Firestone used racing tires made of natural Arizona-grown Guayule rubber at the Indy 500 Pit Stop Challenge in May.

Besides being primarily made of synthetic rubber made from petroleum-derived products, the natural rubber contained in almost all tires comes from tropical sources in South America, Africa, and Southeast Asia, where Hevea or Pará is grown. rubber trees.

Because these trees require a tropical or subtropical climate with at least 47 inches of annual rainfall and no frost, rubber production contributes to deforestation in the Amazon basin and around the world.

About 40% of every tire on the road today is made of natural latex rubber, but Bridgestone Americas is working to develop a stronger and friendlier source of latex that can be grown in the US The source is a plant called Guayule.

“Guayule is a shrub that’s been around for a long time,” said Cara Krstolic, chief race tire engineer at Firestone Tires, a division of Bridgestone. “The tree has a lot of natural rubber in it. So the roots, the stems, the leaves, everything has latex in it.”

Just a great idea

Krstolic told TheDetroitBureau.com developing Guayule has many benefits.

Bridgestone Biorubber Process Research Center
Bridgestone’s Biorubber Process Research Center is working on Guayule-based tire production.

“In addition to tires, we rely on natural rubber for things like surgical gloves and instrumentation,” he said. “If you rely on one species or one genus of tree and there’s some kind of fungus or blight that takes over the tree, it can take away the natural supply of rubber around the world.”

Future-proofing its supply chain is reason enough for Bridgestone to look for alternatives, but there are other benefits at play.

“To diversify our supply and to have a local source of latex, we spent about $100 million investing in Guayule research,” Krstolic said. “We grow it now in Arizona. Another great thing about the Guayule plant is that it doesn’t use a lot of water.

“If you compare it to other crops that are grown in these areas like cotton or alfalfa, it uses about 50% of the water that the crops need. So some of these areas that are affected by climate change, increase temperature, or drought in general, they can grow this plant more easily than other plants.”

If the product is fully developed, the rubber obtained in Guayule will be a direct replacement for the natural rubber that currently comes from the Brazilian rainforest.

“We’re only looking at latex in its pure form, and it should be the same,” Krstolic said. “As long as we process it the same and treat it the same, it should work the same on the tire. That’s the beauty of just looking at the chemical structure. When it arrives, you can get the same kind of performance and the same type of tire that you get from the Hevea flagship. ”

Bridgestone Mesa Guayule Farm is a farm
Guayule can be farmed using existing row-crop equipment, which helps save costs for farmers.

Huge investment in R&D

Bridgestone plans to invest an additional $42 million to build commercial operations, with further investment and expansion planned for 2030. The company will partner and collaborate with local US farmers and Native American tribes to increase the capacity of up to 25,000 additional hectares of land for planting and harvesting guayule at scale.

An added benefit, the crop can be farmed using existing row-crop equipment, which helps save costs for farmers. Bridgestone aims for sustainable commercial production of natural rubber obtained in Guayule by the end of the decade.

“We are very strong in the potential for Guayule as a local source of strategically critical materials, such as rubber, hypoallergenic latex, building material adhesives and renewable fuels, just to name a few,” said Nizar Trigui. , chief technology officer and group. president of business solutions for Bridgestone Americas.

Guayule harvest
Bridgestone aims for sustainable commercial production of natural rubber obtained in Guayule by the end of the decade.

“With Guayule, we can reduce the environmental impacts that come with sourcing abroad while also realizing a more sustainable agricultural system for parts of the country that face continuous and worsening conditions of climate, so it is something that has many benefits for our environment and our economy. .”

Bridgestone has also received several US government grants for Guayule research and development, including from the US Department of Agriculture in 2017 and from the US Department of Energy Joint Genome Institute in 2021.

Tested on the race track

Bridgestone Americas turned to the Firestone racing tires division to test the Guayule-derived rubber under the most accurate conditions of the IndyCar racing series. When IndyCar races on a road or street, fans may notice that some of the tires have red sidewalls. That indicates the driver is using the “alternate” tire compound.

Firestone’s alternative tires have a softer rubber compound than the primary tires, which allows for faster speeds and better cornering, but at the cost of faster wear. Each team will receive a limited number of spare tires to be used strategically during a race weekend.

The green sidewall tires were the first look before making a full competition debut at IndyCar’s Big Machine Music City Grand Prix in Nashville in August.

Firestone Firehawk racing tires made of Arizona-grown Guayule natural rubber were introduced at the Indy 500 Pit Stop Challenge in May 2022. The green-sidewall tires are the first to be seen before making the full competition appearance. which debuted as a red-sidewall alternate race tire at IndyCar’s Big Machine Music City Grand Prix in Nashville in August.

“We want racing to be the ultimate proof point for our technology,” Krstolic said. “IndyCar is one of the most used and demanding motorsport series in the world because they run on street courses, road courses, and ovals, so these tires face extreme conditions. If we at Firestone can put new technology into tires that can handle these racetrack conditions, then we can transfer that technology to street tires. That’s our ultimate goal.”

Bridgestone plans to include Guayule rubber in many of its racing tires by 2023.

Guayule rubber on your street tires

Currently, Bridgestone is expanding the number of local farmers growing Guayule in Central Arizona, and it is targeting 350 new acres of Guayule to be planted by 2023. The conversion to less intensive water that plants is a direct result of Bridgestone’s agreement with the Environmental Defense Fund, a non-governmental organization actively involved in solutions to the lack of water for the Colorado River, which is used for irrigation in Central Arizona.

“The challenge with Guayule is the scaling process,” Krstolic said. “That’s where we put a lot of effort and investment; so that we can ensure that the plant is maximized through selective breeding and reach the most rubber and the easiest process. Now we are in the commercialization phase. We’re going to make some street tires, and we hope to have them on a lot of tires by the end of the decade.

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