BOTTOM BRACKET SHELL WITH BUILT-IN MICRO-DERAILLEUR FOR BICYCLES

摘要

The invention relates to a bottom bracket shell affixed to the lower part of the bicycle frame and essentially comprising a pedal front axle (2) and a rear shaft (7) fitted with a group of idler pinions (6) which are linked to other pinions (4) coupled directly to the front axle (2) or by means of chains (5). The rear shaft (7) comprises a tubular structure and a fixing mechanism to independently connect one of the idler pinions (6) to the rear shaft (7). The rear shaft (7) includes a toothed wheel that transmits its movement to an idler pinion connected to a conventional plate (3) that transmits its movement to a back wheel of the bicycle. Said bottom bracket shell has a simpler shape than other similar bottom bracket shells and provides better transmission output.