Okay, I’ll spill my can of beans. The large oval of the 40’s was made of brass. Sometime in the 50’s, maybe 1955, the large badge changed from brass to aluminum. New for 1961 was the smaller oval and starburst, although some fall 1960 serial numbered bikes had the small oval badge. It went from roughly 3.75” to 3.25” long. This badge also had the circle R off to the side of the N, 3:00 where as the large badge had the R lower than the N at 5:00. Then in 1966 the small badge was issued with word Chicago wrapping the bottom curve. Then for the 1976 models Schwinn stamped the actual build dates in the head badge next to the letter I. This badge was used thru most of the 80’s. Hopefully someone can pin point the year the large badge went to aluminum. Getting into the colors is a whole nuther book. Most of the high end bikes had a badge with a white background and the letters were color matching.