Continental Grand Prix 4000 - 650c: Grand Prix 4000 uses Vectran fiber which is extremely resistant to cuts and tears. Symmetrical tread pattern, shifted to shoulder of tire for increased traction. Colored Grand Prix 4000 tires Use updated Activated Silica Compound (ASC) for improved handling in extreme conditions and lower rolling resistance. All Black Grand Prix 4000 tires use Black Chili Compound which improves adhesion to the road, provides lower rolling resistance and lasts longer. Made in Germany.