Description
The history of rear sprockets and front chainrings for bicycles
2 sprockets
The two sprockets are quite rare.
Initially, when there was no rear derailleur, to change gear you had to flip the wheel, which was equipped with a sprocket on each side.
3 sprockets
3-pinion gears were produced with the invention of the first gears in the 1920s and 1930s, with tooth variation still quite limited. In the case of racing bikes, this 3-sprocket system was often supplemented by the fixed sprocket on the other side of the wheel. The use remained later for touring and walking bicycles.
4 sprockets
The use of 4 wheel sprockets began to spread before the Second World War; Campagnolo's famous stick shifter used this type of freewheel. They remained in use in the 1960s on many racing bicycles and until the 1970s on many touring bikes with rear gear only.
5 sprockets
They made their appearance with the single-lever gearbox (a model later renamed Paris-Roubaix) by Campagnolo, but became widespread in the 1950s with the introduction of the Gran Sport model parallelogram gearbox, also by Campagnolo. In the sixties they became a standard for everyone, they were used for a long time in both racing and recreational bikes. The most famous were those produced by the Regina company of Merate.
6 sprockets
They were introduced in the 1960s by screwing an additional sprocket onto the smaller one of the 5 sprocket system. However, on many hubs it was not possible to carry out this operation without increasing the length of the hub pin itself, to prevent the smaller sprocket from rubbing on the bicycle carriage. Precisely for this reason the width of the hub stop was increased from the standard 120 mm to 126 mm. However, they only became widespread in the seventies.
Anterior crowns
Until the 1950s, racing bikes usually had a single front chainring, often with 48 teeth. Thanks to the innovations of Tullio Campagnolo, the first seals with front crowns were also introduced in the competition field, initially with 52 and 46 teeth. Subsequently, the smaller internal crown was introduced, with 44 teeth and, after 1967, with 42 teeth. . To do this it was necessary to reduce the bolt circle from 151mm to 144mm, as it would not have been possible to fix a chainring with less than 44 teeth to the crank arm
