Michelin advocating for more worn tire safety information

Laurens, South Carolina — Are consumers working with only half a deck, so to speak, when it comes to choosing which tires to buy?

It's no secret that tires exhibit widely varying degrees of performance when new, but how do the same tires perform when half-worn, both compared with themselves when new and with competitors' products, new and used?

That's the crux of a business and technology position for which Michelin has been advocating the past few years.

Now Michelin North America Inc. is taking up the mantle as well under the umbrella #thetruthaboutworntires, a campaign that the tire maker hopes will start a dialogue among tire companies to provide consumers with more complete information about how their tires will perform over time.

Consumers today arguably are better informed than ever before about how new tires perform, but how well do those desirable new tire attributes hold up when the tires are 50% worn? 75% worn? At or near to the 2/32nd inch minimum legal tread depth in most states and provinces?

Those attributes can change drastically as tires wear, Michelin contends, meaning that consumers make purchase decisions based on factors that become less and less relevant over time. Although safety may be subjective from one driver to another, Michelin said, braking distance—especially wet braking—is recognised by most as the best indicator of safety in the automotive and tire industry.

Such was the case recently when Michelin invited dozens of journalists, bloggers and "influencers" to its Laurens Proving Grounds in rural South Carolina, about 60 miles south of Spartanburg.

During that event, Michelin set up wet braking and wet handling demonstrations, comparing new and worn Michelins against new and worn competitor's tires. The "worn" tires were ones Michelin had buffed to 3/32nd inch; the tire maker opted for buffed tires to ensure full-width tread patterns for more equitable comparisons.

The wet braking test pitted four identically prepared 2018 Toyota Camrys, two with new tires and two with tires worn to 3/32nd inch. The test was a full-force stop from 45 mph.

On average, the new Michelin stopped in 78.4 feet on the wet concrete; the competing brand took 104.5 feet. When worn, the Michelin increased that distance to 87.5 feet, a 12% jump, and the competing brand needed 121.2 feet, 16% farther.

The test was repeated with Ford F-150s; the Michelin went from 90.5 feet new to 120.3 feet worn (33% longer), while the competing brand jumped from 109 feet to 141 (29%).

The wet-handling course test—featuring Nissan Jukes—was more subjective, with the assembled drivers experiencing reduced control with the worn tires but with measurably different, and predictable, results.

Michelin has been making noise about worn-tire performance since 2014, since the launch of the Premier A/S with EverGrip technology, which combines a unique rubber compound designed for enhanced wet grip, hidden grooves that emerge as the tire wears down and expanding rain grooves that widen over time.

At that time, then Michelin COO Scott Clark said the Premier A/S tire represented a "significant breakthrough in automotive safety" and a break in the "traditional paradigm" of tire performance over time.

Michelin's internal testing shows that worn tires can be even more unequal in their braking performances.

Michelin's message has evolved over the intervening four years to include economic (removing tires prematurely costs drivers more than €21 billion globally) and ecological (early tire removal takes roughly 400 million tires a year worldwide out of service needlessly) reasons in addition to the safety and performance issues.

Citing this combination of issues, Clark—now chairman and president of Michelin North America—called on the global vehicle and tire industries at the North American International Auto Show to consider adopting testing procedures for partially worn tires.

Clark at that time acknowledged that moving from Michelin-derived testing to independent third-party testing and eventually to an accepted industry standard will be a long and complicated process—a position a number of Michelin's competitors shared.

Nonetheless, Clark said the issue is "something Michelin believes all of us need to start thinking about."

The Michelin leadership reiterated and expounded upon that message during the recent testing at the 3,500-acre Laurens Proving Ground.

While some would question Michelin's strategy as revenue-impairing in the short term, the company argues that serving consumers needs increases the chances of winning them over as repeat customers, which in turn results in increased business long-term.

Tire Business asked Michelin's major competitors to weigh in on the matter.

Bridgestone Americas shares Michelin's belief in the quality and performance of its tires, both at the time of purchase and throughout their life on a vehicle, as well as a commitment to helping consumers make informed purchase decision.

"We do have concerns about the data quality and repeatability of the testing other tire manufacturers currently are proposing," according to Dave Johnson, chief quality officer.

"Artificially prepared worn tires do not duplicate real-world wear and tire performance, and there are other criteria beyond braking distance to consider such as performance in seasonal conditions and driving in deep water, for example."

Tire performance over time is influenced by a number of factors, including driver behavior and proper tire care and maintenance, Johnson said, noting that many consumers "are unaware of the critical role proper maintenance plays in ensuring tire safety and performance over time. "

Bridgestone recently re-launched its consumer education website, TireSafety.com, to provide information on such matters.

Sumitomo Rubber North America (SRNA) views later life tire performance as a "hot topic" for the future of the industry, considering the impact worn-tire performance could have on automated vehicle reliability.

The change of tire performance as the tire wears is due either to the change of rubber thickness as the tire wears or from chemical changes to the internal components used in the tire, according to Rick Brennan, vice president of marketing for SRNA/Falken Tires, who said later life performance is a major project for Sumitomo Rubber Industries Ltd.'s R&D group.

Photo by Bruce Davis, Tire Business The wet-handling course test — featuring Nissan Jukes — was more subjective, with the assembled drivers experiencing reduced control with the worn tires but with measurably different, and predictable, results.

Looking beyond tire performance in isolation, Brennan noted the development of future materials as well as tire design must be integrated with the electronics of the next vehicle generation to optimise performance attributes such as braking performance, traction in bad weather and fuel economy over the life of the tire.

"Developing a structure to communicate differences between tires to the consumer is a much different story," he said. "Creating an information system will require developing testing standards, both for methods and surface requirements, as well as a generally acceptable rating system."

He pointed to struggles the industry has gone through with rolling resistance labelling as an example.

"Although an admirable project to undertake for the consumer, there are many complexity obstacles that need to be overcome," he said, such as what items should be measured and who would do the testing?

Getting some kind of accepted system up and running would be an enormous project, he added, one that likely is not feasible given the number of manufacturers that must participate to make it worthwhile.

Goodyear noted that because a tire must deliver on so many different performance attributes and is subjected to so many differing experiences as it wears, "efforts to meaningfully measure and compare worn-tire performance between tire brands and types have not proven reliable, either in natural wear or shaving tires to simulate natural wear."

Goodyear questioned the use of shaved or buffed tires for comparison testing, asserting that "naturally wearing tires to 2/32nd-inch tread depth before testing is a lengthy and costly proposition, with lots of difficult-to-control variables, like vehicle, alignment, climate, surface, loading, etc."

The tire maker also pointed out that performance differences exist between tire brands and types as they wear due to the unique chemistries of different compounds and sensitivities of different designs.

To help consumers decide, Goodyear said it's important to understand what the tread pattern and depth does in terms of tire performance in different weather conditions—such as on wet, slushy, snowy, icy or gravelly road surfaces, where the tread pattern and depth play a big role in maintaining traction.

Other major manufacturers either declined to comment, did not reply to Tire Business' request or deferred to the US Tire Manufacturers Association to comment.