Sustainable Bicycle Crank Arm Selection Using Life Cycle Analysis Under Typical Cycling Pedal Forces

This research compares the performance of structural steel and general aluminum alloys in identical crank arm designs when bearing loads are applied at different stages of paddling, such as starting, climbing, and racing. Finite element analysis (FEA) was utilized to evaluate fatigue life and safety factors. A design modification strategy was proposed to reduce critical stress in failure zones, resulting in an increased fatigue life. Although steel and aluminum alloys both have significant life and nominal high fatigue life during racing and climbing, respectively, aluminum alloys are unable to withstand a 1815 N starting load, even after modification.