I had a flat at the start of a club ride. I hurried and changed the rear tube while the group waited. Got it going, took off up a longish hill, then on a 30+ mph descent felt a thumping. Stopped the bike and my heart nearly stopped. The bead was hanging out of the carbon rim, but still held air. Gatorskins are strong tires! Released the air fixed the bead, wasted a Co2, and was on the road again. I hate it when that happens. Haste makes waste, and all that.