On the online trivia series, Today I Found Out, host Simon Whistler explains why men’s bikes have a horizontal crossbar and women’s bikes typically do not.
It would seem that having a slanted crossbar like on women’s bikes would make much more sense for men’s bikes, decreasing the chance of racking the guy if he slips off the pedals or the like. However, there is actually a really good reason to have a horizontal crossbar on a bike; namely, the horizontal crossbar ends up adding quite a bit of strength to the frame of the bike. This was particularly important in some of the early bikes, which were often made of significantly weaker materials than modern-day frames, occasionally even being made of wood. (read more)