element tree movement central bicycle and together and together pedivella movement including the central element of tree

摘要

The invention relates to a shaft element (21, 22) of a bicycle bottom bracket assembly (1), comprising a first end portion (29, 30) having first coupling means (25, 26) for coupling with another shaft element (22, 21) and an opposite second end portion (27, 28) having second coupling means (75, 76) for coupling with a crank arm. The first coupling means (25, 26) comprise at least one reference element (38c, 41c) that defines a single mutual coupling position of said shaft element (21, 22) with the other shaft element (22, 21). The second coupling means (75, 76) comprise at least one coupling element (55, 56) having a predetermined angular position with respect to said at least one reference element (38c, 41c).