Most of us don’t put too much thought into how our tires are made, as long as they get us safely from point A to point B. But tires have to perform many functions for a vehicle, including supporting the vehicle’s weight, steering and gripping the road to accelerate and brake, performing in wet and winter weather conditions, absorbing vibrations and impacts, remaining durable for long wear and resisting other conditions such as heat, overload, speed and low inflation.
Ever wonder how your tires do all that at once, and do it well? The answer lies in the way the materials in the tire are selected and mixed, known as tire compounding. Tire compounding is like choosing and mixing the ingredients to make a cake; different ingredients are mixed to produce a compound with specific characteristics. Each component of a tire contains a different rubber compound. And tires on average contain roughly 20 different components.
As reflected in our first-ever Sustainability Report, U.S. Tire Manufacturers Association (USTMA) members are working tirelessly to incorporate more sustainable materials into their tires, demonstrating a strong commitment to enhancing biodiversity and achieving independence from unsustainable feedstocks. This includes ongoing research and development efforts at both the individual and collective levels to identify new sustainable materials that ensure critical safety features.
Dandelions
Natural rubber is a critical component of tires, and it is not domestically sourced in the U.S., but comes to our products through a complex global supply chain. Almost all natural rubber comes from tropical rubber trees primarily grown in the ripe climates of Southeast Asia and Africa, and harvesting the rubber presents challenges to ensure sustainable sourcing. These are key reasons why USTMA members are searching for alternatives to natural rubber.
For example, Goodyear is working with The Ohio State University and other partners of the consortium Program of Excellence in Natural Rubber Alternatives (PENRA) to identify alternative rubber plants to use in tires, like Taraxacum kok-saghyz, a type of Russian dandelion. Continental, together with The Fraunhofer Institute for Molecular Biology and Applied Ecology, Julius Kuehn-Institute, and EKUSA, is also testing tires with treads made from 100% dandelion-derived rubber.
Guayule
And USTMA’s Bridgestone and Pirelli are conducting research on a shrub native to the U.S. Southwest, guayule (pronounced why-yoo-lee), as another potential natural rubber alternative. Guayule has been studied off and on over the past century, most notably by the U.S. government during World War II when Japan cut off natural rubber supplies to the U.S.
Soybeans
If you own Firestone agriculture tires manufactured by Bridgestone, your tires probably contain soybean oil. Bridgestone uses 10% soybean oil, derived from soybeans, to produce its Firestone brand agriculture line. Similarly, Goodyear was awarded a 2017 Environmental Achievement of the Year by Tire Technology International for its unconventional application of soybean oil to displace petroleum oil in the tread compound of tires.
Oranges
Another breakthrough in petroleum substitutes, orange oil, derived from orange peels, is being used instead of petroleum in Yokohama’s tires. And orange oil isn’t just a comparable substitute – it has also been shown to improve a tire’s rolling efficiency, which further increases a vehicle’s fuel economy, while maintaining good vehicle traction. This discovery will likely impact how we make and use tires for years to come.
As traditional resources become more and more scarce, the importance of discovering alternatives for materials found in the brands and goods we rely on each day cannot be overstated. For the U.S. tire manufacturing industry, that means ongoing research into new and sustainable materials to ensure our tires continue to safely power the world’s vehicles for generations to come.