Well, I am going to have to take back that claim about the Serfas tires. I just looked at the tube that punctured last week. It seems that the hole is on the inside diameter of the tube and I can not find any damage on the tire itself. I scanned the inside of the tire while replacing it on the road and could not find any debris that could cut into the tube. Could it be that the impact was hard enough to push the tube into the nipples (through the rim tape) to cause a puncture?