The Celerifere, an early version of the bicycle, was built around 1791 by a French man, Comte Mede de Sivrac. It was basically a scooter with a high seat. There were no pedals---you had to push with your feet like you do with a skateboard or a scooter. Around 1816 Baron Karl Drais de Sauerbrun in Germany added a moveable steering handle. These early machines were often known as dandy horses or hobby horses, but weren't very popular. The improvement that made them popular was added by a Scottish blacksmith around 1839. Kirkpatrick Macmillan added pedals to enable it to get up hills. It was this improvement that made the bicycle a serious form of transportation. Bike were called velocipedes or bone-shakers, because of the lack of the proper tires made for a rough ride! It wasn't until around 1869 that they began to be called bicycles ("two-wheels"). Carriage makers in Paris (either Pierre and Ernest Michaux, or their employee Pierre Lallement) switched the pedal to the front wheel. That's why it is usually either Lallement or the Michauxs, not Macmillan, who are considered as the inventor of the bicycle. In 1869 the penny-farthing or high-wheeler was invented. With the large wheel the rider could go much farther with each push of the pedal, but caused many accidents because the seat was so far off the ground. In the mid-1880s Englishman James Starley manufactured what he called the "safety bicycle" , which had two similarly-sized wheels and a major improvement--- a chain and sprocket  driven rear wheel, with the pedals between the two wheels like modern bicycles. One more historical note---it's possible that the idea of the bicycle was thought of almost 400 years before it was actually invented. There is a drawing of a bicycle-like machine in one of Leonardo da Vinci's notebooks, which dates back to about 1493. Who is recognized as the inventor of the bicycle?
The Michauxs. Macmillan. Comte Mede de Sivac. Baron Karl von Drais de Sauerbrun.