New winter tire from Semperit being launched in autumn 2006: SPEED-GRIP
The Semperit Speed-Grip will be on the market from this autumn, and in initial driving tests the tyre demonstrated very good road holding on icy or snow-covered roads. This is down to the innovative network sipe structure, which means high grip during braking and starting off, combined with safe lateral guidance on typical winter roads. The tread pattern was also designed to provide dynamic handling characteristics on dry roads and good water dispersion when driving in the rain.
Traditionally, the main attraction of Semperit winter tyres has been their safe driving characteristics on snow-covered and icy roads. Developed specifically for road conditions in Alpine regions, they also ensure reliable, safe winter driving performance in the lowlands. In the new Speed-Grip the designers have created a dedicated winter tyre that can not only safely handle fast motorway driving at speeds up to 240 km/h (150 mph), but that also offers extra grip in snow and ice. Traction in snow has been improved by three per cent compared with the tyre's predecessor, whilst lateral guidance is four per cent better. The new compound has enabled braking distances on wet roads to be reduced by four per cent, with aquaplaning protection enhanced by a full six per cent.
Network sipes mean greater grip in snow and ice
The innovative sipe technology used on the Semperit Speed-Grip provides extra grip when starting off and braking, combined with high lateral guidance in snow. "The network sipe structure, where the individual fine grooves in the tread lugs form inclined rectangles, allows individual sipes greater flexibility" explains Akif Celik, developer of the new Speed-Grip. "Under load they form a multiplicity of effective edges that interlock with the ground, thereby ensuring highly positive grip." As the sipes are arranged both longitudinally and laterally, they also have this beneficial effect when a tyre enters a bend and when actually travelling through the bend. Compared with traditional wave-shaped sipes, this technology means substantially greater interlocking with the ground - and thus improved road holding.
Not only do the new network sipes offer advantages when driving in snow, they are also superior to conventional technology on icy roads. The reason for this is that as the sipes are interlinked in the tread lug, the film of water created when braking and accelerating on ice can be channelled away more quickly to the tread grooves. On ice the sipes work like windscreen wipers, dispersing the film of water that would otherwise reduce grip. This means better contact with the ice on the road and subsequently better grip, which helps reduce braking distances.
More tread lugs for better grip
To boost grip even further, the new Speed-Grip has a large number of tread lugs in the tyre shoulder. Under load, these tread lugs form a multiplicity of edges that can interlock with the snow, thereby creating additional grip. A further positive effect of this design is that numerous grooves are formed which can quickly channel water out of the ground contact patch when driving in the rain. The directional orientation of the tread pattern further reduces the risk of aquaplaning.
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