I've read various opinions on this forum as to when to replace a tire. The obvious signs are cracking, seeing the cord, missing chunks, etc. But I also read that when it gets a flattened profile it's time to replace.
I have a set of Continental Ultra Gatorskings (700x25) that I've been riding for about a year. I don't know the mileage, I'd guess between 1,000 and 2,000, but maybe it's less. The tires still look great, except the rear tire is starting to show this flattening. I tried to take a picture, unfortunately it's not from the exact correct angle. What do you think, is it still okay or time to replace? (The second photo is just to show the rest of the tire looks pretty good).