Bicycles and tricycles are both children's riding toys. As distinct types of pedal-driven motion they both appeared for the first time in the 1880s. The tricycle was conceived and produced especially for children from the outset, however bicycles for children were derived by a simple reduction of the scale of the adult counterpart.
After the invention of the modern bicycle with rear wheel chain-driven transmission and a diamond-shaped frame in the 1880s, it quickly entered into widespread use for transportation, work, and leisure purposes. In America, due to the development of private automobiles as the principal form of adult transportation, the bicycle became primarily a child's toy or youth transportation option after the 1920s.
In Europe motorization was slower and the bicycle has been in use for transportation, work, leisure, sport, and play for longer and to a greater extent but with considerable national variation. The use of bicycles for transportation purposes is most pronounced in northern Europe, particularly in Holland and Scandinavia.
Bicycle frames constructed for children appeared immediately after its invention, but it did not become a mass-production item until well into the 1950s. Until this point, children in general were precluded from cycling until an adult frame of small size was manageable in youth. Today the availability of a range of smaller frame sizes enables children from age three or even younger to cycle with training wheels. With further private and public motorization and institutionalization, children's cycling is generally turning into an activity solely of leisure and play. A recent development of significance is the drive towards reduction of risk through safety campaigns and technological innovation, mainly resulting in a range of typically compulsory accessories, such as reflective devices, lighting, and helmets. On the urban scale it has led to the establishment of bicycle lanes in several cities in northern Europe.
Before the invention of the modern bicycle the velocipede enjoyed an enthusiastic following in the late 1860s. Its principle of gearing by upsizing the driving front wheel, has survived among children's riding toys in the tricycle, where this simpler principle of construction has allowed for a cheap product. The element which sets the tricycle apart from the velocipede is the rear transverse two-wheel shaft that provides stability. This eliminates the need for balancing, eases mounting, simplifies starting and stopping and allows children as young as one year old to ride. Tricycles are produced in an extensive number of different forms, materials and qualities; ranging from inexpensive and short-lived indoor plastic models to expensive and durable outdoor models in steel, some with pneumatic tires. Tricycles are typically one-size models for children aged one to three. Until the 1960s tricycles were available in several larger sizes; it was the principal bike of the preschool period. However, in the late twentieth century, bicycles began to cut into this market, as younger children began to purchase two-wheeled bikes.
Dodge, Pryor. 1996. The Bicycle. New York: Flammarion.