Crank assembly for bicycles, in particular road racing bicycles

摘要

The chainset comprises two crank arms (12, 14), a chainring unit (16) and a bottom bracket (18). The bottom bracket (18) comprises a spindle (28) and two bearings (30, 32) for supporting the spindle (28) for rotation in a shell (34) of the bicycle frame. The spindle (28) comprises a middle portion (36) on which the bearings (30, 32) are mounted and a pair of end portions (38, 40) on which the chainring unit (16) and the right-hand crank arm (12) on the one hand and the left-hand crank arm (14) on the other hand are mounted. Each crank arm (12, 14) has a hole (20) for mounting on the respective end portion (38, 40) of the spindle (28). The chainring unit (16) comprises a hub (44) having a hole (42) for mounting on the right-hand end portion (38) of the spindle (28). The end portions (38, 40) of the spindle (28) are made as splined or toothed portions. The holes (20) of the crank arms (12, 14) and the hole (42) of the hub (44) of the chainring unit (16) have a splined or toothed profile the shape of which corresponds to that of the splined or toothed profiles of the end portions (38, 40) of the spindle (28).