I could use some advice on tires. I was just cleaning up a friends bike (the drivetrain), and afterward wiped down the bike. I noticed a "thread" hanging from the rim of the bike. Actually it wasn't the rim, it was from the tire, near the bead. I removed the "thread" which was roughly the circumference of the tire. These are continental GP 4000s tires, and judging by the wear indicators, still have plenty of life in them. So is the casing of this tire unraveling. This friend has a race coming, up so I want to give good advice. Anything to be concerned about on this tire?