Modern Tire Dealer

JUN 2018

Magazine for the professional tire industry

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69 w w w . M o d e r n T i r e D e a l e r . c o m when worn, stops shorter on wet roads than its leading competitors' new tires. At the Laurens Proving Grounds, Michelin tested the new and worn wet traction per- formance of its Premier A/S against a Tier 1 competitor's tire. In all cases the new Michelin tire stopped the fastest, followed by the worn Michelin tire. (It is not Modern Tire Dealer's policy to reveal the names of competitors' tires in competitive testing sponsored by one tire manufacturer. When the compet- ing manufacturer was asked by MTD if the tires directly competed against each other, the competitor said it was not an apples-to-apples comparison. e Premier A/S was described as a grand touring all- season tire featuring premium wet traction, while its tire was a "high performance all-season tire with performance emphasis weighted toward responsive handling." e competitor then offered up a tire that it felt was appropriate to test against the Premier A/S.) Tire Rack's view on the 4/32nds versus 2/32nds debate hasn't changed, even aer testing the Premier A/S on its home track. "Premier A/S and its companion line Premier LTX do have some unique features in the tread that go a long way to mitigate the effects of tire wear when the tire encounters that volumetric event," said Woody Rogers, Tire Rack's director of tire information. "But no tire is as good at 2/32 as it is when new. Tire performance in the wet isn't like gasoline, where the last ounce works like the first gallon. Tire traction in wet evolves as the tire wears." Rogers said he has already seen a trend toward full-depth features in the tread, "as all major brands have found the need to maintain as much traction as possible into the late stages of the tire's wear life." TESTING METHODOLOGY Bruner said Michelin's first goal is to make people aware of how important worn tire performance is. "You can get worn or used reviews on so many other things you buy as a consumer. Why can you not get information about a worn tire? It's the piece of technology you place your life in every time you get in the vehicle. "As we make people aware of that problem, and the very practical considerations related to that problem, we believe it will lead to independent third-party tests on worn tires. And we believe as that occurs, our conversation will probably begin leading naturally into what would be the testing methodologies." Carter said ASTM (American Society for Testing and Materials) standard F1046-01, "Standard Guide for Preparing Artificially Worn Passenger and Light Truck Tires for Testing," would make credible wet traction testing on worn tires less burdensome. It's a good place to start. "Testing worn tires could be useful," said Tire Rack's Rogers. "But the key is to develop tests that are meaningful to the consumer, and replicate what they will experience in the real world aer three to four years — or more for high-mileage tires. "Is shaving a tire the same as wearing it down and exposing it to the environment and heat for that many years? What's the right depth to test at? ink about going from 3/32 to 2/32. It's a 33% reduction in depth, and essentially the same reduction in void volume. e impact of remaining tread depth/void volume is not linear. e loss of performance ramps up dramatically as you wear away each of the final few 32nds of usable tread." Jim Frady, Michelin's tire performance team manager, said the ultimate goal is much less complicated. "We made design choices years and years ago to get to the level of worn performance that we are at today. So the goal is to get the whole industry making those choices, so people are safer." ■ "Technology exists to design and manu- facture tires to perform well in wet conditions, even when worn," said Tom Carter (right, pictured with Eric Bruner, center, and Andrew Koury). Michelin's wet traction testing data revealed how various tire brands performed new, at 3 mm (between 4/32- and 3/32-inch) and worn (2/32-inch). "There is a meaning- ful, significant amount of variation in these stages among all of (the) tiers," said Eric Bruner, Michelin's director of external communications. In addition to reduced stopping distance, there are other issues to consider when removing tires prematurely, says Andrew Koury, Michelin brand director for Mi- chelin North America Inc. They include the following. Cost to consumers. "Twenty-five bil- lion dollars are wasted every year in pulling a well-maintained tire off the road too early. The cost to drivers is around one tire every two years or $250. It's a high cost." Cost to the environment. "There are 400 million tires wasted each year by early removal. They have to go somewhere. Imagine 400 million tires in landfills." Koury says the cost in raw materials used to rebuild the 400 million tires removed prematurely equals close to 35 million tons of carbon dioxide emissions globally, "which is equal roughly to the entire New York City's emissions for six months." A costly decision Why removing tires too early matters

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