A fixed internal gear hub comprising a fixed axle, an input member and an output member each rotatably mounted about the axle, an epicyclic gear system comprising at least one sun gear, rotatably mounted about the axle, planet pinions disposed in a planet cage and a gear ring. The gear ring is connected non-rotatably to the input member. The planet cage is connected non-rotatably to the output member. A clutch enables the input member to be selectively non-rotatably connected to the planet cage and a selector key enables the sun gear to be selectively locked rotationally to the axle. The hub provides two fixed gear ratios and further fixed gear ratios may be provided by adding an additional sun gear or gears.