I have a friend who is getting his bike ready for a 7 day trip through Oregon. Last night, he was checking his tires and found a tiny piece of glass IN EACH TIRE. Neither had worked its way through to the tube yet, but who knows in the next 500 miles?
Now, I keep my bike pretty clean. But I will admit I don't check the tires very carefully when I have the Giant up on the rack. I just now went out to check them over. Guess what? A 1/4 inch cut in the tire, right about where the sidewall meets the part that touches the road (I don't know the name of that part). It wasn't all the way through, but I could see it was just about to make it. I put a sticky boot on it and am confident it will last, but I will keep an eye on it. This Conti GP 4000 s has about 1800 miles on it, so I would like to get another 1000.
PEOPLE! Go check your tires right now and report back.