The 1980s Michelin ads picturing car tires as infant playpens, with babies surrounded by belted radials and black rubber, always ended with an invaluable lesson: “Because so much is riding on your tires.” It’s as true today as ever, only there’s an extra weight we didn’t consider back then: The federal government.
-For the first time, the United States will attempt to ban passenger vehicle tires that aren’t fuel-efficient. The FAST Act, signed into law by President Obama in December 2015, is a five-year transportation bill that, among many things, directs the National Highway Traffic Safety Administration to set minimum standards for tire rolling resistance by the end of 2017. It will attempt to mirror tire regulations adopted by the European Union in 2012, which mandated thresholds for rolling resistance, wet traction, and even noise. This ignites a very reasonable suspicion. Will low-grip tires with “eco” labels on the sidewall—some of which are already fitted as original equipment on efficiency-minded mainstream cars today—come to ruin all cars, especially sports cars? Surely, our skidpad results and slalom times would all suffer.
-But after reviewing trade group opinions of the EU regulation and speaking to a few experts, we’re not sure any of that will happen. When these new regulations go into effect (likely in five years), our tires and cars should overcome whatever may get lost—fuel consumption included.
-“We are first and foremost a safety product,” says Mike Martini, president for Bridgestone’s original equipment division in the U.S. “We got to have this fuel economy component, but you got to do it without compromise.”
-Why go after tires? With significant strides made in aerodynamics and other sources of efficiency-sapping friction, modern cars have gotten to the point that their tires burn up a bigger proportion of fuel than they used to. According to Michelin, tires typically account for 25 percent of a new car’s fuel consumption, up from the 20 percent it was a few years ago. Put another way, every fourth fill-up in your Accord goes to overcome rolling resistance. On electric vehicles, which are further optimized for efficiency, and where every last mile is critical, tires drain around 30 percent of battery range.
--
In Europe, all car tires ship with consumer labels that score a tire’s fuel efficiency and wet traction across an A to G grading scale, along with a three-tiered scale for allowable road noise relative to future limits. Tires that score below a G—that’s a rolling resistance greater than 12.1 kilograms per metric ton—can’t be sold in the EU. According to the EU’s calculations, the best “A” grade tires may reduce fuel consumption by 7.5 percent compared to the lowest “G” grade. Multiply the billions of miles we travel worldwide by even a sliver of improvement in gas mileage and the savings are massive. Bridgestone goes so far to claim that its Ecopia Plus tires can net drivers an additional 20 miles over a 400-mile cruising range. (Of course, if every driver checked their tire pressures each month the potential fuel savings could be massive as well, but what American does that?)
-Our government isn’t likely to require noise reduction or so many letters. An earlier, separate directive intended to supplement the Uniform Tire Quality Grading System—the numerical treadwear rating and two alphabetical ratings for temperature and traction imprinted on each sidewall—is also under consideration. New five-star ratings will be displayed for fuel efficiency, wet traction, and treadwear. These ratings may not coincide with the actual efficiency and traction thresholds proposed by the FAST Act. But whatever regulators ultimately decide, we’ll have the first standard that’ll let us compare a tire’s fuel efficiency against its competitors. Winter, off-road, spare, light-truck (“LT” designation), and any tires less than 12 inches in diameter are exempt.
-Car enthusiasts shouldn’t cry, at least not until the first ruling draft is published. The wording in the FAST Act specifically mandates that any new standards won’t have a “disproportionate effect” on tires rated Z and higher (i.e., those with speed ratings above 149 mph). That wording was explicitly lobbied by the Rubber Manufacturers Association, which represents the majority of tire companies selling in the U.S. The bill’s language for wet-traction requirements also scales them with fuel efficiency, so that any increase in efficiency must prevent a decrease in wet traction. Since wet surfaces have a lower friction-coefficient than dry surfaces, it’s a tougher—and ultimately, safer—benchmark for tire companies to meet. In essence, lawmakers can’t mess with our P Zeros, Pilot Super Sports or Sport Cups, or any of our favorite sticky rubber. If they try, the RMA and other companies can challenge NHTSA or file suit against it under the Administrative Procedure Act, which strictly governs how government can make its own rules.
-“The market for [high-performance] tires could be negatively impacted compared to the rest of the market,” says RMA spokesman Dan Zielinski when we asked about the impacts of future regulations on high-performance tires. “The last thing we wanted to see was a tire company to trade traction for fuel economy.”
-Michelin is hardly worried about its performance tires. According to global technical sales director Scott Pajtas, rumblings of the EU law capping grip levels are untrue. The regulations, he says, have made the biggest impact on Chinese, Korean, and other emerging, low-cost tire brands flooding the market, which are struggling to meet the rolling-resistance threshold.
--
“For the last 25 years, we’ve operated under the assumption that these regulations would be tougher and tougher to meet,” he says. “The EU rules set performance thresholds for a second-tier tire supplier. Frankly, it’s not necessary for us to increase rolling resistance even on high-performance tires.”
-But tire companies don’t operate above the laws of physics, and there’s no magic formula to make a tire class-leading in every category. Spider graphs, which link dissimilar performance values, are an easy visual of this challenge. How can you possibly increase wet traction while lowering rolling resistance? Can you boost treadwear and dry traction simultaneously? Bridgestone’s Martini, who started in the tire business when the first low-rolling resistance models came out in the late 1970s, says his industry is up to the challenge.
-“We’re going to be doing more and more to meet that 54.5 mpg [CAFE] target,” he says. “They’ve already turned the crank on us really hard, and we’ve already delivered.”
--
- -
- The Rosetta of Rubber: How to Read a Tire Sidewall
- -
- Goodyear Dreams of Spherical Tires for Self-Driving Cars
- -
- Monsters of Grip: Nine Summer-Performance Tires Tested
- -
-
Besides lightweight materials and advanced polymers—the most secret sauce in a tire company’s lab—automakers will continue to optimize their suspension geometry and tuning toward specific tires, even if they deliver fractionally less grip than before, to maximize every millimeter of contact patch. Stability control and anti-lock brake tuning, too, will have get to smarter to perfectly match a tire’s “slip curve,” which measures the exact point at which a tire exceeds its peak traction and the grip begins to fall off.
-We’ll be watching—and measuring, with our test gear—this evolution of tires very closely. Because, indeed, there’s a lot riding on them.
-
originally posted onhttp://blog.caranddriver.com/the-future-of-tires-will-the-government-limit-grip/
No comments:
Post a Comment