Two-wheeled carts have been around for over 3 500 years, so why did it take so long to invent the two-wheeled bicycle?

One of the inherent properties of a vehicle is that it must be stable, especially if it is used on rocky, sandy or cobbled roads, as was the case until about two hundred years ago. Carts had two wheels but these wheels were side-by-side and were connected by an axle. The wheel span, in turn, formed a stable triangle with the draft animal, so it was able to negotiate rough roads with ease.

From the late 1600s onwards there was an explosion in the development of horse-drawn vehicles in Europe, North America and South Africa and vehicular transport became socially acceptable. But inventors have a need to go one step further and they soon began to think of horseless carriages. 

Bicycles are inherently unstable as they have two wheels in line. Inventing such a vehicle over 200 years ago would have been preposterous, equivalent to having a horse with two legs, both on one side. Improvements in roads, the availability of new materials, rapid advances in technology during the First Industrial Revolution, and a paucity of horses, all facilitated the invention of the first bicycle by Baron Karl von Drais in 1816.