Continental Grand Prix 28 Folding Tire. The Continental Grand Prix is a tire that is made for every ride, whether training, commuting or long distance. It builds on the technologies and insights of the Grand Prix 5000 family, features the BlackChili Compound and a 3-ply construction that offers good puncture protection and rolling resistance. Tread pattern inspired by iconic Grand Prix 5000. Puncture resistant with new 3-ply construction. Range of use: Road bike. Technology: 3-ply Puncture Belt. 28-622: 6.5 bar. 30-622: 5.0 bar. 28-622 / 700 x 28c. 30-622 / 700 x 30c. 1 x Continental Grand Prix 28 folding tire. Note: This tire is suitable for hookless rims up to a limited maximum pressure. Please refer to the fitting instructions and tire packaging for detailed information.