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The GT Radial winter series has been confirmed with the already well-known Champiro WinterPro model. For rims from 13 to 16 inches to cover the widest range of cars in the mid-small segment

Duilio Damiani

THE RECENTLY ended coldest season of the year has confirmed the growth of a market dedicated to seasonal products and, consequently, the ever-increasing use of winter tyres – which is also thanks to current laws and local regulations. A trend that is destined to be an even bigger confirmation of the value of models that at one time were described simply as “snow tyres” designed specifically to give the best performance, not only on snow-covered roads, but also in the various weather conditions typical of the cold season. 

Presented at the end of 2010, the Champiro WinterPro will be consolidated in diameters specifically dedicated to the A, B and C segments of the automobile industry, supported by the rigorous tests to which the entire GT Radial range for the European market is subjected. 

We were given a practical verification of the WinterPro’s characteristics during a presentation to a restricted number of representatives of the trade press and the sector’s commercial operators, which the Asian company’s top management held in March on the winter track at Ivalo in Finland. In evocative arctic scenery, Ivalo is situated 300 km north of the imaginary Arctic Circle demarcation line where winter seems to be as permanent as the midnight sun. In parallel with the European Technical Centre at the Mira test circuit in Great Britain, it is here that GT Radial products are developed and undergo the umpteenth test before being sent to their definitive destination in all the Old Continent’s markets.

After landing on the icy runway of the small provincial airport in this freezing arctic scenario, it was immediately clear to us that here was the sum total of all the conditions that winter can throw at us, from wet asphalt made slippery by frost to sheets of ice covering the road, something that unprepared drivers fear the most, especially when braking suddenly or coming out of a bend at full speed. The rigours of winter were partly mitigated by the imminent arrival of spring, which was of little comfort given that the temperature stayed well below freezing and hardened the molecules of all matter. Offered by Test World (, the Finnish website used by all the international automotive world’s main players to find the most severe test conditions, the Mellatracks complex is studded with permanent tracks. There are long, straight stretches that are completely frozen over and kept as smooth as glass by machines with brushes, for testing braking performance in conditions where there is absolutely no grip. There are also snow-covered circuits for testing lateral grip on fresh and packed snow and, lastly, mixed circuits of different lengths that simulate driving on ordinary roads that are more or less taunted by the white snowflakes that are the incontestable masters of this outdoor environment.

The vehicles we used represented the typical vehicles targeted by GT Radial winter tyres: a squad of two- and three-box Ford Focus 1.6es with front-wheel drive, and a turbo-diesel BMW Series 3 with rear-wheel drive. We were separated into small groups so that we wouldn’t get in each other’s way on this intense day of dynamic tests.  We were able to take turns driving the different vehicles in the variety of situations offered by this exceptional location that reproduces in the eyes of every  driver a real inferno of ice.

Along with the Champiro IcePro, the studdable tyre for Nordic markets where temperatures are icy for most of the year and which we are unlikely to see in Italy, with the possible exception of some locations further north, the real protagonist of the situation was the well-known Champiro WinterPro, a model that has been in product lists for a couple of years now. For next season, WinterPro sizes have been optimized for mid-size and mid-small saloons in order to meet the widest applications also on the Italian market.

Its directional tread with the characteristic elliptical grooves works like a pump to rapidly expel water from the shoulders by centrifugal force. Tread geometry offers considerable acceleration and effective braking in typical winter conditions on dry and wet roads, snow and slush, where the contact patch is optimized by the characteristic grooves between the blocks. There was good perception of grip limitations during the slalom, which allowed us to zigzag smoothly even on snow that had been compacted by being repeatedly driven on. There was only a natural and gradual tendency to under-steer, which was corrected simply by easing pressure on the accelerator.

Featuring a tread compound with GT Radial’s new NanoTek Silica technology, the soft surface of the Champiro WinterPro tread stays supple in very low temperatures to maintain grip even on frosty roads. The model has good safety features, with 8% more efficient braking on wet, 9% on dry, and a 4% increase in resistance to aquaplaning. Vehicles with extreme performance levels could not have expressed their full potential on extremely slippery surfaces, but with the feistier rear-wheel drive BMW there were no particular qualms and over-steering was corrected by regulating the wheel. Straightening up when coming out of a bend was never brusque with the WinterPro and at full speed the vehicle came to a stop surprisingly quickly at the end of the straight stretch after a decisive push on the brake pedal.

Listed in 43 different sizes, the winter GT Radial winter tyre is available for rims from 13 to 16 inches, from 145 to 225 mm in width and with a shoulder ratio of between 50% and 80%. A decision that intentionally positions it in the mid segment of the car market. By winter 2013/2014, the newly announced Champiro WinterPro HP will be available for rims from 16 to 20 inches for sport utility and high-range vehicles. As GT Radial directors like to emphasize, this is not a development of the current WinterPro, but a completely new product with specifications optimized for the high range. But this is another story that we will tackle “on the rocks” in due time.

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