As I understand the early postwar springers had the skinny truss rods like the the pre-war bikes. The headtube length is different between pre and postwar as well as the piece under the headtube theat the legs attach to. I believe all postwar springers fit either girls or boys whereas prewar have different headtube lengths between the two. I'm sure I could find other differences as well ans the real Schwinn experts can certainly enlighten us. V/r Shawn