The ring gear is also known as the pinion and is located on the rear wheel. Bicycles with derailleur gears always have several sprockets. The sum of the existing sprockets is called the sprocket set or cassette.
// Construction
With the cassettes (several sprockets or sprocket set), a distinction is made between sprocket sets that are firmly connected to one another and loose sprocket sets. With the gear rim packages that are firmly connected to one another, it is not possible to change an individual gear rim. The entire cassette must always be replaced. The advantage of this design is that assembly is very quick and there is less risk of assembly errors.
Cassettes with loosely connected sprockets are mainly used in racing bikes, so you can also change a single sprocket. In this case, the correct sequence of the sprockets and the correct positioning of the intermediate discs must be observed during assembly.
// Capacity of a sprocket pack
With derailleur gears, a distinction is made between large and small capacity of the sprocket set. The capacity results from the number of existing teeth per sprocket. We speak of a small capacity when the number of teeth is very small (example: sprocket set with sprockets from 11 to 29 teeth). The greater the difference in the number of teeth of the individual sprockets, the greater the capacity (example: 11 to 36 teeth).
While racing bikes work with small capacities that enable finely dosed gear steps, mountain bikes use large-capacity sprockets.
// sprocket and chain
It must be ensured that the chain used fits the mounted sprocket set. Conventional chains can be used for cassettes with up to eight sprockets. Cassettes that contain more sprockets require a narrower chain.
Further information can be found at www.bikelexicon.com