Shimano Nexus is a brand of bicycle components which includes products such as epicyclical gear hubs, cranksets, shifters, brake levers, hub brakes, hub dynamos, and a CPU for automatically changing gears. The series is primarily aimed at the "comfort" market such as urban commuters and tourers, and as such is not made to withstand the rigours of off-road or mountain biking. Unlike the Alfine range of products, neither gear hub of the Nexus-series is disc-brake compatible.
In 1995, Shimano rolled out its Nexus line of seven- and four-speed internal hubs. Shimano had manufactured three speed hubs prior to that, and these hubs were at that point rebranded Nexus. In the early 2000s the 8-speed Nexus hub gear was introduced, having three stepped planetary series mounted downstream of each other. The hub was operated with a standard twist shifter. By November 2006, The Nexus range came in several ranges (Inter 3, Inter 7 and Inter 8) providing 3, 7 and 8 speed models respectively.
Inter 3 - This hub has three speeds with 36% intervals and an overall gear range of 186%. It weighs 1220 grams stripped.
Auto 3 - The hub is fitted with a 3 speed automatic gear system, which utilizes a front hub dynamo to power a CPU that automatically changes the three speed internally geared hub.
Inter 4 - Nexus Inter 4 hubs had four speeds. It has been discontinued.
Inter 7 - The Inter 7 comes in two versions with either a steel or aluminium shell, weighing 1860 and 1460 grams respectively, the latter more expensive yet relatively reasonably priced. The gear mechanisms are operated with a Revo Twist Shifter or a simple non-ratcheting trigger shifter and are identical in the two versions, offering a range of 244% with non-even interval percentages of 17,14,17,16,17,16.
Inter 8 - The Inter 8 has interval percentages between the gears of 22,16,14,18,22,16,14, and a total range of 307%, comparable to a road bike derailleur gear systems, but as the other Nexus products, it is designed and intended for urban commuter use. The hub comes in a variety of versions, weighing between 1550 and 1990 grams stripped.