The comments about the "giant" big ring are chuckle-worthy. Keep in mind that the smallest cogs available back then were 14 teeth. 60/14 = 47/11 = 51/12 = 55/13, so it's not THAT big a gear! Back in the 70s, I was the first one in town with a 13t high cog, and my current "old man" high gear is a 46/11 - only marginally lower than 60/14!