Originally Posted by
Dave Cutter
In the 1950's when I started riding... bicycles were toys (in America)... period. But even in 1964 when I was 13... and got my Schwinn Varsity... road bikes were catching on (mostly with college kids). Although road bikes were still rare and road racing wasn't heard of to speak of (in America). I am pretty sure older kids, teens, and college age young adults were who those road bikes where marketed to through-out the 60's. After all... they were advertised in comic books.
In the 70's, (young) adults found the cycling sports and marketing (successfully) targeted that market. But handlebars did remain narrow(er). So (you're correct) it must have been a aero concept/trend. I had heard both claims that it was for better aero dynamics... and from other longtime cyclist that is was simply because of the youth market/buyers. But hadn't really thought about it.
I was too general too, surely there would be regional differences, especially between places where road cycling was a popular sport, compared to those where it was a youth activity or a method of transport. It would be interesting to compare stock bikes from the 60's and 70's sold in the US to those from Italy, France, or Eastern Europe (and not just regarding bar width).