I was cleaning and adjusting my bicycle today and a thread came loose on the sidewall of BOTH tires - about 1/8 inch above the rim. The thread was about the thickness of a thin human hair. This is kinda like the loose thread you find on your socks or your underwear. So I pulled it off. On both tires the thread came off almost all of the way around the circumference of the tire.
Is this "normal"? Should I be worried enough about this loose thread to just change the tires outright? Or should I wait until there are other signs of stress/wear?
These are good tires - Continental Grand Prix 4000 with only about 800 miles on them and plenty of tread left. I am a big guy - 225+ lbs - and I have already dealt with a sidewall blow-out 2 years ago on my previous pair of Michelin's (not the tire's fault - a car ran me off the road). I love to ride far and fast - so blowouts to me are a major buzz-kill.
Your opinions are appreciated.