All tires are black. Except this one from Yokohama is also green. And orange. Where a typical contemporary race tire would be 100 percent synthetic (including synthetic rubber), Yokohama's new environmentally friendly slick, dubbed the Advan ENV-R1, uses 15 percent natural materials. So that includes natural rubber and orange oil.
Real McCoy rubber, the stuff that grows in trees, has plenty of durability, but is harder than its man-made counterpart. This affects grip. So Yokohama's development team decided to add orange oil. Why? Allow Mark Chung, the company's corporate planning and strategy director, to explain: "On a molecular level, orange oil is very similar to natural rubber. Yet it can make the rubber softer, improving grip levels."
It's taken some time to get to this point. Work began on this project 20 years ago, before most people had heard of global warming and the Prius wasn't even a glint in a Toyota engineer's eye. It really didn't come to, um, fruition until the 2008 24-hour race at Tokachi, Japan, where a Nissan 350Z shod with this compound (which Yokohama calls Super Nanopower Rubber, or SNR) came home fourth. "Motorsport is ideal for research and development," says Chung, "where innovations can be tested to their utmost."
That Tokachi result emboldened Yokohama to go further for this year's racing calendar, by supplying teams in the Patrn Porsche 911 GT3 Challenge (Gruppe Orange, Orbit Racing/Tequila Patrn and Snow Racing/Universal Industrial Sales) and sponsoring Panoz Team PTG's ALMS endeavors. "It's a great opportunity to highlight the performance of our eco-friendly tires," says Chung.
So how well do they perform? "From lap four, when the tire really reaches its operating temperature to the last lap, there's hardly any variation whatsoever. Maybe a tenth of a second here and there, but it has outstanding consistency." says Chung. "Racers can have fun with it and still be safe. The GT3 drivers have thrashed the hell out of these tires, trying to make them break, and they've stood up to the beatings."
There has to be a down side, right? Surely they're more expensive. Says Chung: "They're cheaper than the tires they've replaced." What about the manufacturing process? "We're very mindful of making as small a carbon footprint as possible. Even the orange peel, which would normally be thrown away by the local juicing plant, we take and extract the oil from it." And because it has more elements from nature, it makes recycling easier too.
Motorsport hasn't historically enjoyed a reputation for being eco-conscious, but it has provided the average driving Joe with plenty of goodies over time, like variable valve timing and double-clutch transmissions. This tradition continues with a road-going version of Yokohama's green tire that consists of 80 percent natural materials, out this summer and looking like it will be called the E-Spec. "Its rolling resistance is very low," says Chung, "22 percent better than the O.E. tires on a Prius."
But the big question is: Do these new tires smell of oranges? "Only when you peel out," says Chung.