Two speed hubs were the first geared hubs of the world, in 1898 already the first 2-speed hub was produced in England named ‘The Hub’. The simplest geared hubs only contain one simple planetary gear train which is only operated in one direction: this only provides one direct gear and a speed reducing or a speed increasing ratio. One simple planetary gear train – unidirectional So hubs with one simple planetary gear train were the first historic internally geared hubs and they are still produced in their millions. In 1902 the first 3-speed hub was produced carrying the name ‘The three speed gear syndicate company’, which later on became Sturmey-Archer. Mister Johnson from the USA received a patent for a two speed with one planetary gear train hub in 1895. As already mentioned in Planetary gears this kind of coupling leads to many diverse possibilities of gear grading.ĭoppeltorpedo planetary gear train ONE SIMPLE PLANETARY GEAR TRAIN In other cases there are some hubs containing gear trains which are differential coupled: a very close ratio for example is realized by connecting the sun gear 1 of gear train 1 with the planet carrier 2 of planet train 2 in the 3-speed model SturmeyArcher AC. In both gear trains the planet carriers are joined together thus achieving a total ratio by multiplying the single ratios. The first one provides 2 speed reducing ratios (output 1: Planet carrier 1) and the second one provides 2 speed increasing ratios (Output 2: Ring gear 2 and input 2: Planet carrier 2). The Shimano Nexus Inter 7 for example contains two stepped gear trains. Model 29 achieves the same number of speeds by using a stepped planetary gear train being operated unidirectional with speed reducing ratio only.Ĭoupling of planetary gear trains: in hubs with several gear trains the individual gear trains are often piled behind one another, i.e. The well-known model H311 from Fichtel & Sachs achieves three speeds by using a simple gear train operated bidirectional. This is mostly to be found in common 3-speed hubs. both directions of translation are applied, e.g. A gear train can also be operated bidirectional, i.e. This is applied in Fichtel & Sachs Automatic or Duomatic hubs for example. only one direction of translation is applied, e.g. The Sturmey-Archer model FM achieves the same number of speeds by using two simple gear trains joined together differential.ĭirection of power transfer: a gear train can be operated unidirectional, i.e.

In the Shimano Nexus Inter 4 for example four speeds are realized by a stepped planetary gear train. – Type of gear trains: As already mentioned simple gear trains and stepped gear trains are employed, as well as combinations of both. More complex hubs contain several gear trains thus achieving even more speeds – but different grading as well. By a triple stepped planetary gear train seven speeds can be realized. – Number of planetary gear trains: in the simplest case a geared hub only contains one simple gear train achieving two or three speeds. Thus there are some important parameters, which will be described here briefly: how many gear trains it contains, how these gear trains are joined together, etc. The gear structure shows the layout of a specific hub, i.e. Other sections reveal the basic function of geared hubs and showed several variations of the technical implementation of different speeds.

Itrain unidirectional