The performance of the studded tyres used by the World Rally Car crews at Rally Sweden has impressed manufacturers Michelin and Pirelli.
Milder-than-normal temperatures beset the FIA World Rally Championship’s only true snow rally last week. With snow and ice giving way to underlying mud and gravel on the stages, there were concerns that grip would be compromised.
Before the rally got underway, eventual winner Jari-Matti Latvala explained his concerns: “Gravel comes through the snow and ice and offers great grip, but at the same time it destroys the tyres quickly and pulls out the studs.”
But fears about tyre performance were largely unfounded and both Michelin and Pirelli have drawn some pleasing conclusions.
Jacques Morelli, the manager of Michelin’s rally programme, said: “Because of the general state of the roads, studded tyres were absolutely necessary. That said, it’s true that the conditions were more aggressive than expected and the drivers could have ended losing a fair proportion of their studs but that didn’t happen.”
Morelli believes the impressive performance of Michelin’s X-ice North 2 studded tyre in Sweden owed much to the technology that’s employed to fix the studs into the tyre rubber.
“This year’s studded tyres lost 10 times fewer studs than the tyres used in comparable conditions on the same event less than 10 years ago,” Morelli explained. “The gluing process we have developed helps to keep the studs in the tread blocks – even when the tyres are used on stony ground.”
Pirelli supplied its ‘Sottozero’ studded tyres to Henning Solberg’s Ford Fiesta RS WRC and this marked the first time the Italian manufacturer’s rubber had shod a World Rally Car in the WRC since 2010.
Senior tyre engineer Matteo Braga, said: “We were very happy with the stud retention and the quality of the studs. We experienced no problems in this respect and that was very satisfying.”