| 摘要 |
A bicycle crank comprises a mixture of aluminum and chromoly. The spine comprises chromoly, which serves as a backbone to the crank arm and thereby provides added strength. The body comprises aluminum, which reduces the crank arm weight. The body can therefore be thinner and lighter with the added support provided by the steel spine. In another embodiment the crank arm includes a spine having a crank boss and a spindle boss at opposed ends that are integrally formed with the crank arm. An outer shell includes an elongated member having an inner face having an outer perimeter with a shape approximately coincident with an outer perimeter of the spine The inner face is recessed to admit a portion of the spine and has crank and spindle boss apertures extending through to an outer face. The outer perimeters of the outer shell and the spine are joined together.
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