Why are men's and women's bicycles built differently?

The crossbars on bicycle frames give them added strength. On a man’s or boy’s bike the crossbar extends straight across the top of the frame, just below the seat. On a woman’s or girl’s bike the crossbar is attached to the seat tube at an angle, far below the seat. Because of this structure, women’s bikes are not nearly as sturdy as men’s bikes.When bicycles were first built, women didn’t wear pants; they always wore skirts or dresses. The low crossbars on their bikes allowed them to get on, ride, and get off with dignity—without showing their underwear! The design of bicycles for women and girls, then, is based on a long-standing tradition and still offers the advantage of easier mounting and dismounting. But today, women and girl bicyclists wear pants or shorts when riding and can easily use bikes designed for men. As a matter of fact, serious female bicyclists who do a lot of riding or travel through tough terrain and need bikes with sturdier frames buy those made for men.