Anti-wear polymers: Michelin introduced new X-Ice Snow winter tires

The first winter tires appeared in 1933 in the depths of Michelin, a year before the Finns from Suomen Gummitehdas Oy, now known as Nokian Tyres, produced a similar model. The tire was designated Michelin N and became the first winter tire with protruding blocks to enhance grip on the road surface. Interestingly, this design was used unchanged until the 50s!

The Michelin brand was the first to cut lamellas on the tread blocks to improve the tire’s traction. Summer tires were first lamellazed, but after the success of the Michelin XH all-season tires, which were designed for both asphalt, snow and ice riding and featured zig-zag lamellazing and anti-slip slip-resistant seat nests, it became clear that winter tires also needed to be cut. As a result, in 1994, the first model in the Michelin Alpin family was introduced, whose tread had many Y-shaped lamellas which, as they wore down, increased the number of clamping edges and thus maintained the tire’s traction throughout its service life.

One way or another, today winter tires are part of the product lines of all leading companies. They are divided into several distinct groups. Firstly, they are tires designed to use anti-slip studs and tires whose tread can run on ice and snow without studs. It is clear that for European countries with mild climate winter tires without studs are better suited. In fact, in the vast majority of such countries the use of studs is prohibited. But the problem is that in some countries with a harsh climate studs are also prohibited! As a result, winter non-spiked tires are divided into “European” and “Nordic” models, capable of operating in severe frost conditions.

Well, what do the drivers of Russia, Kazakhstan and Belarus choose, where studded tires are quite legal? In principle, approximately 75% of the demand for winter tires in this zone is for studded models. But, firstly, 25% are quite a decent amount, because the total market volume of winter tires in this group of countries is 24 million, and secondly, within this zone there are areas where the demand for non-spiked models can exceed 60%. This is the entire Far Eastern region, where the focus is largely on Japan (and there are no studs used), southern regions (the southern Volga region, Kalmykia, Krasnodar and Stavropol Territory, North Caucasus), as well as Belarus. But in regions where the ball is ruled by spiked models, there is a significant contingent of buyers who choose options without spikes. The generalized portrait of the buyer of non-spiked tires looks like this: it is a resident of a big city, relatively rarely faced with pure ice and snow drift. As a rule, he owns a modern car (often – from the premium brand line), equipped with perfect assistance systems. Accordingly, one of his priority values is acoustic comfort (the level of road noise produced by studded tires is much higher). Finally, he is an experienced driver who knows how to fight skidding and not to bring the situation to the point where he will lose control over the car. Accordingly, the share of premium tires among non-spiked tires is slightly higher than among studded tires.

This forces designers of all global tire brands to continuously improve their products and regularly bring to market new and improved models of non-spiked tires, while trying to bring the efficiency closer to studded versions. At the same time they are struggling with the noise that spikes make… Who will win this struggle and the eternal cholivary of “velcro” and “velcro” – it is still unclear. But the market entry of any new model of studless tires is quite obviously interesting. It is clear that new tires of such famous brand as Michelin could not be left without our attention.

The premiere of new Michelin X-Ice Snow tires took place in the vicinity of a small town Umeå in the north of Sweden. Frankly speaking, the organizers were very worried: the weather again showed its unpredictable burrows, and two days before our arrival Umea was watering the real rain. But in the end it was merciful, and the ice road on Lake Tavelsjön didn’t melt, though there were some puddles left on it. The tire that we were about to meet should replace two models in the Michelin product line at once, the X-Ice XI3 and Latitude X-Ice XI2, and come close to some ideal of an unspoiled winter tire. What are the criteria to meet this ideal? According to Michelin specialists, buyers who choose shoes for their car pay attention to the following parameters. First of all, the tires should effectively provide braking and handling both on ice and in loose snow, and the car should be able to make steady turns. But lately, one more parameter is becoming more and more important: the wear resistance and preservation of the tire characteristics throughout its life cycle. After all, unspiked tires cling to a slippery coating, first of all, due to sharp edges of lamellas in blocks of tread, and as they wear out, coupling properties of the tire with the road inexorably deteriorate. As a result, Michelin specialists have made their main slogan “High performance level despite wear”. In their opinion, the new tire should provide a high level of handling and effective braking not only during the first season, but also in all subsequent seasons, up to a tread depth of 4 mm. Well, taking into account the increased wear resistance, this should, in theory, enable the tires to operate for at least one season longer than the competitors’ products. But here the designers face a seemingly insurmountable contradiction: increased wear resistance requires increased rigidity of the rubber compound of the tread, and the stiffer the rubber compound, the lower the coefficient of adhesion with the coating. As a result, work on new tires always goes in two directions: the development of tread design and the improvement of the mixture itself. This is how the work on the new Michelin X-Ice Snow was structured.

Let’s start with a tread pattern. The designers abandoned the design with a central drainage groove and arranged the blocks as a slightly asymmetrical Latin letter V. The blocks themselves have deep lamellation and are cut with two types of 3D lamellae. The first type lamellas, called U-shaped, allow to maintain the necessary rigidity of the block during maneuvering, improving controllability, and the second type lamellas, having variable thickness, effectively drain the water film on the ice surface. In addition, these lamellas provide a “sticky effect” when clogged with snow. The depth of the lamellas allows to keep the pattern until the most critical wear, i.e. until the residual tread depth of 4 mm is reached. But the edges of the lamellas will still lose their sharpness, and here comes a new composition of rubber mixture, which received the brand name Flex-Ice. This compound has a formula based on a new generation of elastomers, which allow maintaining elasticity even at very low temperatures and have a high stiffness at moderate temperatures. And the less dense polymers contained inside the embedding form microner layers as they wear, which effectively absorb the water film on ice and create additional edges clinging to the snow. As a result, the wear and tear of the working edges of the lamellas should be compensated by the appearance of micronerisks on smooth areas of blocks.

And this approach has borne fruit. According to Michelin, the braking path of the X-Ice Snow tires (when braking at 40 km/h) in its new state is only 10 cm shorter than its predecessors, the X-Ice XI3 and Latitude X-Ice XI2. But when worn up to 4 mm of the residual depth of the tread, the win on snow increases to 60 cm, and on ice – up to 1.5 m!

The X-Ice Snow also looks good compared to its competitors. Frankly speaking, in its new condition, it cannot claim to be the champion in terms of basic parameters: it is definitely superior to the Continental VikingContact 7, and the Nokian Hakkapeliita R3 shows almost the same performance. But the X-Ice Snow has the lowest rate of traction degradation, and after one season of operation, Michelin is already moving into a confident first position. Only the Bridgestone Blizzak WS90 shows a smaller drop in hitch performance as it wears down, but in its new condition, the tire is ranked last, and in second place it is selected only by the fourth season, after which it is already time to go for recycling.

We were able to see the fairness of these statements from our own experience. At first, we took the 27-kilometer route around the lake with the Audi A8 cars wearing the new X-Ice Snow. We drove the convoy along the roads surrounding the lake, strictly following the prescribed speed limits. The coverage was very different: pure asphalt, asphalt with rolled ice hillocks, pure ice sections, and rolled snow graders, somewhere sprinkled with granite chips, and somewhere – in natural form. And during the whole route I never once felt that the car was going to get out of control. In short, just driving, calm and confident … But I fully felt quite good acoustic comfort, as well as the fact that even on the ice hillocks the car walked very softly, despite the low profile of the installed tires. We evaluated the handling on the winding ice road behind the wheel of the VW Golf. Again, the same feeling: nothing supernatural, but the corners equipped with the X-Ice Snow car runs very smoothly. Somewhere you can send it to a controlled skid and then stabilize the car with gas. In short, complete predictability even in areas where the rolled ice hides under a layer of water. But we appreciated the main advantage of the new tires during the third exercise. This time we had to brake on ice at a speed of 40 km/h. The Audi Q5 participants in this test were wearing three brands of tires (Michelin X-Ice Snow, Continental VikingContact 7 and Nokian Hakkapeliita R3) with a minimum permissible tread depth of 4 mm. The vehicles were equipped with electronic devices that signaled the start of emergency braking and measured the braking distance. It was possible to perform two runs on each type of tire. It must be said that the results of each particular race depended on many factors: how quickly you responded to the beep and moved your foot from the accelerator to the brake pedal, the intensity of acceleration, the force with which you pressed the brake, and how accurately the car was held on the polished wheels ice tracks. It is clear that if instead of smooth ice under the wheels is snowy tiny, the braking distance will be much shorter. I personally have the best results with Continental VikingContact 7, second place for Michelin X-Ice Snow, third place for Nokian Hakkapeliita R3. Some of the participants of the test had the best braking on Finnish brand tires, others had the best braking on French brand tires… But when the organizers summed up the results and calculated the average results of all races, the following picture appeared: for Michelin X-Ice Snow the average braking distance from 40 km/h was 31.2 m, for Continental VikingContact 7 – 33.6 m and for Nokian Hakkapeliita R3 – 34.5 m. Let me remind you that we are talking about tires worn out to 4 mm. For the new tires, the numbers and the position distribution would be quite different, but it is these numbers that confirm that Michelin’s strategy of “High Performance against Wear” is still working and that the new tires can be used for at least one season longer.

Well, in conclusion, a few words should be said about the options for the new tires. First of all, buyers will get two versions, simply X-Ice Snow (designed for road cars) and X-Ice Snow SUV, which, as the name suggests, is designed for installation on crossovers and SUVs. These versions differ only in that X-Ice Snow SUV has a reinforced inner frame. As for dimensions, during the first year of production, the version for cars will be presented in 56 sizes, from 155/65 R14 to 255/40 R20. And the maximum choice is observed for the diameters R17 and R18; 12 dimensions will be completely new, in which the winter non-spiked Michelin tires have not been produced before. Tires for crossovers and SUVs will be available in 38 sizes, from 215/70 R16 to 285/45 R22, and 20 sizes will also be new. In this category, the focus was on the R20 diameter: of the 15 available sizes, 11 will be new, indicating that the main target audience for Michelin X-Ice Snow SUVs will be owners of premium and luxury crossovers and SUVs. And in the following year, 2021 to the announced set will be added 46 more standard sizes. As for price growth, the company assures that customers loyal to the brand will not feel it, because the X-Ice Snow should not cost more than 3% more than its predecessors. Whether it is or not, we will see when the new tires will appear on the shelves of the tire dealerships.

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