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08/03/2012
FOR LM-80 READ BLIZZAK MULTIPURPOSE

WINTER TESTS FOR BRIDGESTONE
Between Cortina and the surrounding area, we took part in some convincing tests of the most recent range of winter tyres from Bridgestone. The flattering results were confirmed by the debut of the Blizzak LM-80 tyre for SUVs and AWDs: this is our report

Mino De Rigo

If it is true that, as the Romans said, “repetita iuvant”, or repetition is useful, then it would be wise never to forget how winter tyres behave compared to their summer counterparts in weather conditions typical of the cold season. A concept Bridgestone applied to the organization of a workshop with trials on public roads and private mule tracks in the Belluno area between Cortina and Misurina. A large group of Mercedes’, from the short G to the Ml and the B Class, with the C Class saloon and 2WD and 4Matic station wagons in between, was used to test different types of vehicles and traction systems on cold, wet, snow-covered and icy roads. A suitable occasion for putting the Blizzak Lm-32 winter tyres through their paces and especially the new Blizzak Lm-80 tyres which replace the previous Lm-25 4x4 series for SUVs, CUVs and AWDs. A complex test bench that once again confirmed the now well-known theory that fitting your vehicle with winter tyres at the appropriate time equals guaranteeing greater safety for yourself and other road users.

 

Safety

The guarantee of short braking distances, increased grip even on hills, more steering and control on snow and ice was the result of the combined action of a tread created to give good grip when temperatures drop, with grooves and sipes that provide traction on snow-covered and icy surfaces, and compounds that give balanced performance in different environmental situations, including driving on wet and dry roads. What was most striking about the summer-winter test, which favours the latter when it is cold and even without snow, was the comparison on snowy ground.  For the sake of objectivity, a braking test with ABS was carried out by an independent testing centre on an Audi A4 saloon equipped with new and used summer tyres. It was repeated with a new set of winter tyres and then a set with 50% wear. The vehicle had to go from 35 km/h to 5 km/h on snow; the results left no room for any doubt: the 13.1 metres needed by the vehicle with pristine winter tyres (in this specific case, Blizzak Lm-25, 225/55 R 16) increased to 14.8 with the tread 50% worn, to 36.5 metres with new summer tyres (the Er300 of the same size) and even 42.1, well over three times further, with worn summer tyres. It’s worth thinking about. Even more so after we drove the Mercedes C Class on a winding, ice-covered up and down track and felt the winter tyres grip where it had been difficult to stay on our feet just a minute before.

 

Multiple technology

The feeling of safety was exactly the same in the Mercedes Ml fitted with the Blizzak Lm-80 that is making its debut on the Italian market. Recognizable by its very open, unidirectional tread (which helps drainage) and dense, wide criss-cross grooves, the new tyre has a lighter casing for less rolling resistance and, in particular, “washboard” technology applied to the tread blocks: a solution that increases the number and depth of the grooves that are essential for performance on snow and ice, but without affecting the stiffness of the contact area and dynamic performance on dry and wet roads.

It is based on the special shape of the multidirectional grooves which, instead of having the customary accordion-like pattern that generates a high number of edges but give the block a certain amount of movement, are reminiscent of the interconnected zigzags of a washboard, a shape that allows the high number of edges to be combined with greater block stability. It is also useful to remember that traction on snowy roads is the sum of the effect of the edges, which are responsible for the micro-meshing of the sipes that grip the ice, of surface grip, with the blocks functioning like a rack, and of macro-meshing achieved by snow compacting between the grooves.

 

Dual compound

Available for rims from 15” to 20” in the series from 70 to 40, the new Lm-80 is accredited with an optimized profile to avoid localized load concentrations, in other words to give better weight distribution, and with a dual compound. The external compound is very rich in silica so that it performs better at low temperatures, and the one below the tread gives better heat dispersion to the advantage of smooth running and, therefore, reduced consumption. The nature of this tyre can be described as considerably multifunctional, just like the Lm-32 developed in collaboration with BMW and launched last year for a long list of vehicles from the Audi A3 to the Aston Martin Rapide; a run flat version will also be available soon. Where constant winter use on the most difficult surfaces is envisaged, the Bridgestone candidate is the Blizzak Dm-v1: an extreme product for off-roads and SUVs, is uses the micro-porous Multicell Z compound which integrates a new polymer that will, according to the designers, distribute the silica more evenly in the compound. Additionally, cross “Z” sipes and the special groove distribution contribute to meshing and therefore increase grip.

 



• More growth for winter tyre market 


Helped by the different and more knowledgeable attitude of road users, but also and primarily by regulations that have flooded almost all Italy’s regions, in 2011 the winter tyre segment achieved a new record. And if, according to research company Gipa, about 7% of car owners have made the changeover with tyres they already had, then over 8% have bought new tyres, double the figure for last year. In the space of five years the composition of the car and AWD market has become 87.1% summer and 12.9% winter tyres, a ratio of 67 to 33. If sales in the product segment, as revealed in a survey by Gfk in 2010, were composed of 65% premium summer tyres, then 6 sets of out of 10 were winter tyres. A lower figure that is justified by less availability of premium products and, even more so, by the lower cost of winter tyres in the standard and budget categories, which represented 22% and 18% of total sales, respectively.

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