Grand Prix Road Bike Tire The racing classic and handmade in Germany. The name Grand Prix has become a brand of its own in cycling circles worldwide. The Grand Prix is the classic tyre marking quality and performance. A great all-round tyre for all-year use. With their PolyX Breaker bring PKW know-how to the bike tyre arena C Polyester has been used successfully for years in car tyres and been tried and tested many times. The extremely resistant polyester fibre is woven tightly crosswire making a very high fabric density which not only makes the Breaker more resistant to foreign objects but is also resistant to punctures. The rolling resistance is not effected either by the PolyX Breaker. refine newly developed synthetic rubbers with natural rubber with the proven high-performance tread compound. They use these rubbers with special nanometric carbon soot particles which are optimized in shape and surface properties for best uses for the intended tyre. BlackChili Compound reaches an unprecedented of performance. Tyres with BlackChili Compound reach an unprecedented level of performance. Compared to the previous best Activated Silica Compound BlackChili tyres have 26% less rolling resistance a 30 % higher friction value grip and a 5 % increase in mileage.