Fullerton, California-based Yokohama Tire Corporation has developed a method of rubber compounding that uses citrus extracts derived from orange peels to produce automotive tires.
Tire makers have long know that orange-oil extracts, when compounded with rubber, produced a composite that was suppler and held the promise of improving fuel-economy. Conventional wisdom, however, held that gripping ability would suffer.
Yokohama’s orange-oil technology was first utilized in its premium-grade DMA dB super E-spec tire. In 2008, the company debuted its production model DNA Earth-1 tire which the company claims has a rolling resistance “21% lower than with an industry benchmark for affordable fuel-saving tires: Yokohama’s own ECOS tire.” In addition to improved fuel-economy, the tire also offered better gripping ability.
The orange-oil technology has also allowed Yokohama to reduce its dependence on petroleum in the manufacturing process. Approximately 20 gallons of petroleum go into the production of an average set of automobile tires. Extrapolated over a 10 million-vehicle market (approximately all the new light vehicles sold in the U.S. in 2009), 5 million barrels of crude oil would be required to fit each vehicle with a set of four tires.
Yokohama estimates that by compounding natural rubber with orange peel extracts, it has reduced the amount of petroleum used in the production of its dB Super E-spec tires by about 80%.
Yokohama’s director of strategic marketing Mark Chung says, "We’ve been working on this technology for 20 years."
In addition to testing the technology under normal driving conditions, Yokohama has also submitted them to high speed testing including the Porsche GT3 series races.
Chung says that Yokohama’s orange-oil compounded tires offer advantages over other eco-tires. He says, "Most eco-tires are just a harder compound, which means they have less grip until they heat up. But the base temperature of an orange tire is better. It’s also stickier at heat because the natural rubber and orange oil interact."
He also said that “orange tires” provide superior braking performance, wear better and weigh about two pounds less than standard, original-equipment tires. He said that, in a closed-course test of an orange tire fitted Mini Cooper S, the tires provided exceptional control and a well-balanced feel. He did admit that the tires were slightly more prone to squeal when placed under severe duress. When fitted on a Toyota Prius, the orange tires reduced roll resistance by 22% over standard tires which translated into improved fuel-efficiency.
Yokohama produces its orange tires at a zero emissions manufacturing facility and derives the necessary orange-oil extracts from peels acquired from orange juice bottlers. Chung jokes, "It’s not like we’re growing orange groves to do this."
Orange tires are currently available as replacement tires for the Toyota Prius, Honda Civic Hybrid, Honda Insight, Nissan Versa and Mini Cooper. Orange tires are priced slightly higher than standard replacement tires. For example, a common replacement tire for the Toyota Prius is the Goodyear Integrity tire costing an average of $74 per tire. Yokohama prices its dB Super E-spec tire at $105, but the higher purchase price is easily offset by fuel savings over the life of the tires.