  Michelin Premier All Season. Click image to enlarge |
Review and photos by Lesley Wimbush
GREENVILLE, South Carolina – You’re probably familiar with the image of a coin, inserted within a tire’s treads, as the most recognized way to measure their depth.
But a new tire from Michelin might just help you put those coins back in your pocket – where they belong.
Tires represent a considerable investment necessary to the safe operation of your vehicle. Unfortunately, the very characteristics that make them effective can also be the things that tend to wear out faster. And a worn tire is one that’s seriously compromised when it comes to performance and grip – especially on wet pavement.
“Tires play a significant role in safety,” said Ron Margadonna, Michelin’s senior technical marketing manager. “They’re only new once, and as they age, safety degrades, especially in the wet where most accidents happen.”
The Premiere A/S (all season) introduces a trio of new, patented technologies that not only extend the life of the tire, but actually help it transform as it wears to reveal new layers of grip. Bundled together under the name “EverGrip”, the technology targets three key aspects of the tire’s construction.
1. Almost all tires use the radial ply construction, a design that was invented by Michelin in 1946. Where they differ is in their outer layers, the tread compounds that give the tires their performance characteristics.
Most use varying amounts of rubber, carbon for color and durability and silica for grip with some kind of softening agent so they stay malleable. Silica, whose widespread use was begun by Michelin in 1992, is a strengthening and bonding agent which improves rolling resistance and therefore lowers fuel consumption.
Michelin first started using sunflower oil for flexibility with the introduction of the Primacy lineup. The Premier A/S uses high amounts of silica, giving the treads the strength needed for wet traction, and sunflower oil – which adds the pliability to grip at lower temperatures. The high-traction compound is meticulously mixed to ensure a consistency throughout the tire’s wear.
2. There’s a lot of engineering that goes into a tire’s tread pattern. There are grooves to channel away water, blocks of tread to give stability and “sipes” – ingenious slits cut into the blocks that expand to increase road contact and help to evacuate moisture. This adds up to some 30 percent “void area” – the amount that instead of contacting the road is dedicated to channeling away water, snow or mud.
  Michelin Premier All Season. Click image to enlarge |
As treads wear the grooves tend to get narrower (cutaway resembles an upside-down valley whose narrow apex is at the top) with the “void area” decreasing to roughly 15 percent. Narrow grooves lose their effectiveness at channelling away water, resulting in a tire that hydroplanes on wet pavement.
Michelin maintains its 30 percent void efficiency, by taking the traditional groove and literally turned it upside down – so that as the tire wears the channel widens and retains its ability to remove water.
3. Probably the most interesting aspect of the EverGrip Technology are the “emerging grooves” – more than 150 rain grooves located along the tire’s shoulder. These extra grooves, which lie hidden beneath the outer layer of compound, emerge as the tire wears to provide an unexpected boost in wet traction later in the tire’s life.
