Good morning. Today we're going to look at the history of the bicycle. Although we often think of the bicycle as a relatively modern invention, its origins go back to the early 19th century. The first two-wheeled vehicle, called a 'draisine' or 'hobby horse', was invented by Karl von Drais in 1817. It had no pedals; riders pushed their feet against the ground to move. Later, in the 1860s, pedals were added to the front wheel, creating the 'velocipede'. However, this design was quite uncomfortable due to its rigid frame and wooden wheels. It wasn't until the 1880s that the 'safety bicycle' with a chain drive and two equal-sized wheels became popular, making cycling much safer and more accessible to the general public.
❓ ¿Cuál fue el principal problema del 'velocípedo' mencionado por el conferenciante?