I have tried a number of the Conti range and they all seem to have the same issue. Once they wear past a certain point (~3k miles) you only have to look at them and they puncture. In a way it is a good thing cos it tells you, when you are on your third puncture in 5 miles, that the tyres need replacing. the rest of the time though they are fantastic, especially the 4S, although 4000s and Attack/Force are good too (just not available in the size you want. Fast rolling and grippy, way better, IMHO, than Michelin Pro2s or Rubinos.