| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to easily notice the wear of a bicycle crank arm. SOLUTION: The bicycle crank arm 1 has a first end portion 25a to which a bicycle crank shaft 23 is mounted, and a second end portion 25b to which a pedal 27 is mounted. The crank arm 1 includes a core material 35, and an outer peripheral material 41. The core material 35 is arranged so as to extend between the first and second end portions 25a, 25b. The outer peripheral material 41 has an inner layer 43, a surface layer 45, and a marking layer 47. The inner layer 43 is formed so as to cover an outer peripheral portion of the core material 35. The surface layer 45 is formed so as to cover the inner layer 43. The marking layer 47 is disposed between the inner layer 43 and the surface layer 45. COPYRIGHT: (C)2005,JPO&NCIPI |
