Bicycle gearing
Gears appeared in bicycles already in the early 20th century, but were rarely used in Estonia before the 1950s-60s. There are three ways to add gears to a bicycle.
Change of gears with chain. More than one sprocket is mounted on the rear wheel (occasionally to the chainring towards the pedal), which lead the chain to desired sprocket. This system is very common today. It came to Estonia through hiking and sports bicycles of Kharkiv factory in the 1950s. However, it is likely that there were some bicycles with regular Torpedo freewheel equipped with a block of three sprockets available already in the late 1930s. Such a system had been developed already in the 1920s, but it was uncommon back then.
Gearbox near pedal cranks. Here, the cranks do not have direct connection to the front chainring. Instead, there is a gearbox with gears between the chainwheel at the cranks (usually for 2-3 speeds), switch lever of which is mounted on the frame. This system was used in some bicycles from the 1920s-50s (e.g. German Adler), a few of them were also found in pre-war Estonia.
Internal gearing in rear hub. One internal planetary (epicyclic) gear system allows using 2-3 speeds. Torpedo started to manufacture two-speed rear hub already in 1904 (a year after patenting standard freewheel hub), three-gear rear hub became widespread in the 1920s. There were only a few such bicycles in Estonia before the war – a considerable amount of such bicycles consisted in a batch of English Humbers (with three-speed B.S.A. gear hub) and Raleighs (with three-speed Sturmey-Archer gear hub) in the 1920s-30s, both gents and ladies bicycles. It is most likely, that there were only a few two-speed Torpedo-hub bicycles in pre-war Estonia.
In the 1940s-50s, when gear hubs (with epicyclic gears) became widespread in the world, the Soviet Union was isolated from the Western countries and only a couple of such bicycles arrived to Estonia in the 1950s-70s (most likely by seafarers).
