In 1862 while Lallement was employed building baby carriages in Nancy he saw someone riding a dandy horse, a forerunner of the bicycle that required the rider to propel the vehicle by walking.
Lallement modified what he had seen by adding a transmission comprising a rotary crank mechanism and pedals attached to the front-wheel hub, thus creating the first true bicycle.
"[3] Both the novelty of bicycles and their early precariousness is conveyed in the following excerpt from the book titled The Mechanical Horse by Margaret Guroff:[4] That fall, Lallement conducted a road test of about four and half miles, pedaling the velocipede mostly uphill to a nearby village of Birmingham (now part of Derby) and then doubling back home to Ansonia.
As he told a journalist twenty years later, his delight during one bumpy downhill stretch turned to panic when he realized that his brakeless vehicle was about to rear-end a horse-drawn wagon.
He yelled a warning to the two men in the wagon, then veered and tumbled into a roadside culvert filled with water, cracking his head in the process.
[citation needed] David V. Herlihy presented evidence at the fourth International Cycling History Conference in Boston, Massachusetts, Oct. 11–16, 1993, that Lallement deserves credit for putting pedals on the dandy horse.