The Grand Prix 4 Season Clincher Tire is a step above the tried and true 4000 when it comes to durability and flat resistance. It is ideal for racing in unpredictable conditions, and it's even better for training when the winter muck starts to thaw. The Grand Prix 4 tire features a 330TPI threads per square inch double layer Vectran belt under the tread. This proprietary fabric is a liquid crystalline polymer that features high levels of tear resistance at a low weight, making it ideal for racing as well as training. To take the Grand Prix 4 to the next level of rider satisfaction and beef up puncture resistance, Continental reinforced the sidewall with DuraSkin, a polyamide fabric that keeps road grit and grime from penetrating to the tube.