Ars Technica APRIL 2023 / by JONATHAN M. GITLIN / Read original article
In 2022, tire company Bridgestone used the IndyCar racing series to debut a new sustainable natural rubber that it has been testing as a replacement for less environmentally friendly rubber. The new tires used rubber from a desert shrub called guayule (Parthenium argentatum). Now, Bridgestone is ready to try the rubber in a more practical application and has produced a demonstration run of road-going tires using guayule rubber and a high percentage of recycled materials. The company will conduct tests with automakers to prove the concept.
The world produces about 2 billion tires each year, and while synthetic rubbers are used in modest amounts, most road tires use a lot of natural rubber from the para rubber tree (Hevea brasiliensis). But 90 percent of para rubber is grown in Southeast Asia and has to be shipped around the world to reach tire factories.
Bridgestone has been looking at guayule as an alternative for a little over a decade now. The guayule plant is a short, woody shrub that grows easily in the deserts of the American Southwest and requires much less water than crops like alfalfa or cotton that are also grown there. In Arizona, Bridgestone has been breeding guayule and conducting research and development on its use in tire-making.
More than just natural rubber
In fact, these new tires incorporate more than just guayule rubber. Bridgestone says that 38 percent of the tire’s content is biological in origin—there’s some para and guayule rubber, but also plant-based oils and resins, biologically derived silica from rice husk ash, and biologically derived carbon black.
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