Continental puts wear indicators in their GP4000 tires. When the wear indicators disappear, you can just start to see casing threads coming through the tread rubber. Continental disagrees with you. Also, how would you know, 1000 km in advance, that casing threads would appear after 1000 km more riding? IME a lot of people throw out tires well before they are worn out, saying "they're WAY squared off" and such, without a clue as to how many more km/miles the tire could be ridden.davidka said:If the cords are showing the tire should've been replaces 500-1000km ago.