Originally Posted by
rm -rf
Continental GP4000 tires have
wear indicators. When these two holes are worn off, the tread rubber is almost completely gone, so the tire is ready to be replaced. Maybe other Continental tires have these, too?
And one of the holes is deeper than the other. By the time the first hole is level, I will likely have started getting flats, and the tire will have squared off a bit. I replace if I get a couple of flats that weren't from major debris.