Originally Posted by rufus
today's steel is extremely thin. the headtube is the thickest tube on the bike, and brazing them there, or having them cast into the head tube lugs leaves the thinner downtube free from possible damage done by the torch, either by over cooking by the builder, or just the general weakening that happens to most steels after being exposed to heat.
+1
The Serotta rep told me that they started doing it because people were having frames fail where the braze-ons were attached at the downtube. Putting them on the head tube solves the problem.