Nashville-based Bridgestone Americas is a step closer to having vehicles rolling on domestically-produced natural rubber. The company is cultivating its own alternative to the rubber tree: a desert shrub found in the American Southwest.
The humble guayule plant — pronounced why-YOO-lee — looks a bit like sagebrush or tumbleweed, and the foliage has to be processed to extract the rubber ingredients. By comparison, rubber trees are simply tapped, similar to the process of harvesting maple syrup.
Research on the guayule plant’s rubber properties has been going on for decades. But tire companies have an incentive to put in the extra work: They don't want to depend solely on a plant that grows in Southeast Asia, says Bill Niaura, director of new business development for Bridgestone.
“Conceptually, it makes sense to diversify our supply base for natural rubber,” Niaura says.
In 2013, the Japanese company — which has its U.S. headquarters and several tire plants in Tennessee — started planting its own supply of guayule on 281 acres in Eloy, Ariz., where the plant grows wild. Now the company has built the first functional tires from that rubber. One of its competitor, Cooper Tire, is also working on guayule rubber.
It will still take a decade or more before mass production begins, Niaura says.
“Realistically, we’ve always talked about sometime in the 2020s because the challenge is really that large," he says. "It’s akin to building a new industry in the U.S. There is no domestic natural rubber industry.”
This isn’t the first time tire-makers looked to guayule as a rubber source: During World War II, cut off from Southeast Asia, the U.S. began experimenting with plant-based alternatives. That process ultimately led to petroleum-based rubber, which is widely used today. But natural rubber is still needed for the largest industrial-grade tires.