A Worn-Out Tire that Acts like a New One
Last month, Michelin took the first step in trying to revolutionize the tire industry.
The idea is a rather simple one that has eluded the world’s top scientists for decades. What if a tire never degraded in performance as the tread wears down? That is exactly what Michelin hopes to accomplish with the brand’s latest passenger car tire, the Premier All-Season.
Unveiled last month at the North American International Auto Show, the magic behind the new Premier tire is a technology called EverGrip. As the tire wears, its tread pattern changes to ensure great wet weather performance remains throughout the life of the tire. Michelin is making the rather bold claim that this is as big of an advance in tire technology as the invention of radial tires and silica compound. Basically, the manufacturer sees this tire as the clichéd “game changer” in safety innovation.
Built as a successor to the Primacy MXV4, the Premier line of tires will hit shelves the first of April across America. It’s designed to be Michelin’s safety line-up of tires with the key element being that as the tire degrades, its safety does not. The Premier’s compound consists of copious amounts of silica and sunflower oil. It has as much silica in the tire as the polymer can handle. As a quick refresher, silica is a key component in wet performance traction while sunflower oil allows for better flexibility of the rubber at lower temperatures.
The Transforming Tire
But plenty of tires contain those ingredients these days. What really sets the Premier apart from the competition is the tread changing technology. As the tire wears, the four center grooves grow wider and over 150 extra side ribs become exposed to compensate for water evacuation from the shallower tread depth. Most tires, including the Premier, have around a 30 percent total void area that does not contact the road. This is the area dedicated to water, mud and snow evacuation. Most tires shrink down to roughly a 15 percent void total when worn. The new Premier tire remains at 30 percent even all the way down to 4/32nds tread depth.
This doesn’t mean the tires need replacing at that level however. Michelin claims these tires are designed to operate admirably right down to the wear bars. In fact, the emerging grooves do not become uncovered until after the tires are halfway to being fully worn, or around 5/32nds tread depth. Those out there like us that questioned how the tire would perform in the dry with so much contact patch being lost as the tire wears down fear not. The diagonal grooves on the two bands flanking the center band actually disappear and become solid as the tire wears down to compensate rubber lost in other areas. This allows the overall void area to remain at the aforementioned 30 percent instead of increasing to something like 40-45 percent. The tread footprint of the tire when half worn out looks quite different than the footprint when it is new.
Better Worn Than New?
Speaking of new, Michelin is making another bold claim about the new Premier tire. The manufacturer is confident that even when half worn, this tire will perform better in wet conditions than many competitor’s brand new tires. Ballsy claim indeed and one we couldn’t wait to put to the test. So when Michelin invited us down to the company’s Laurens Proving Grounds in South Carolina, we couldn’t say no.
As we arrived at the facility, a row of shiny Cadillac CTS test cars greeted us. Two tests are laid out on the flooded track, one a wet autocross and the other wet panic braking. The Premier is being put up against two other tier one tires, the Goodyear Assurance and the Bridgestone Turanza Serenity Plus. For both tests, the Michelin Premiers were scrubbed down to 50 percent tread to be pitted against new Goodyear and Bridgestone tires. All tires are mounted on the same sets of wheels and tire pressure is a standard 35 PSI.
Putting the Claims to the Test
First up was the sprinkler-drenched autocross course. After taking a turn behind the wheel of each car fitted with the three different tires, the worn Premier exhibited the best steering response and grip level. The Goodyear Assurance only lags behind the Michelin slightly in grip, but falls off rapidly when approaching the tire’s adhesion limit. The Bridgestone had less grip overall, but not much falloff at the edge of grip compared to the Goodyear. Either way, the worn Michelin isn’t just comparable to these new tires when it comes to wet cornering grip and braking, but actually slightly better. As a final party trick to show how good the Premiers are when new, Michelin wheels out a forth CTS equipped with a new set of Premier tires and lets us have at it. As one of my colleagues commented, compared to the other tires, it feels like we are driving around in the dry out here, not a monsoon.
But me telling you how good these tires feel are on wet pavement is thing, hard indisputable numbers are another. That is what the second test is all about. Three passes would be made in three Cadillacs, once again wearing the Goodyears, the Bridgestone and the half-spent Michelins. In standing water at 53 mph, we are to hammer the brakes and come to a complete stop. Our 50-0 mph distance would be measured to show how long each tire takes to stop. As can be expected from a Michelin backed demonstration, the half-worn Premiers walked away with it. On average we stopped in 98.2 feet with the Premiers compared to 105.2 feet with the new Goodyears and 109.1 feet with the Bridgestones. That is nearly a car length shorter stopping distance.
As proven by the test results, Michelin may be on to something with this tread changing tire technology. It is the first successful attempt at inverted grooves as far as Michelin is aware since items like the tire mold requires some engineering trickery. A concern we had with the inverted treads was that under hard driving the rubber covering the hidden grooves would crumble and chunk off. After a day of abuse at the hands of unrelenting automotive journalists, we did not notice any unusual damage to the sidewalls of the Premiers and the hidden grooves remained just that – hidden.
When the tire hits retailers in April, it will initially be available in 32 sizes in diameters ranging from 15 to 18 inches and come with a 60,000 mile limited warranty. At a starting price of $156, the tire is slightly above the tier one industry average for an all-season tire. But, like most things in life, you get what you pay for. If safety is more important than value in an all-season tire that delivers exceptional wet weather performance through its entire tread life, the Premier cannot be beat.
1. The Premier will be available April 1st, 2014
2. It will initially be available in 32 sizes ranging in diameter from 15 to 18 inches
3. Price for the 185/65R15 with be $156