The stiffness of a bicycle frame is a major factor of a bicycle performance related to safety, stability, and weight. In this study, the torsional and bottom bracket stiffness of a bicycle frame were experimentally investigated. The torsional and bottom bracket stiffness for 63 bicycle frames were evaluated and analyzed by measuring the displacement of frames. The torsional stiffness is related with turning performance and the bottom bracket stiffness is related with power transmission. The experimental results show that the average stiffness varies up to 20 % according to the frame materials and types. The torsional stiffness has a strong corelation with the bottom bracket stiffness even though they have different effects on a bicycle frame. It seems that the experimental results can be applied to the quality criteria of racing bicycles and also design standard of a bicycle frame.

• 권경배(Dept. of Energy System Engineering, Graduate School of Seoul National University of Science and Technology) | Kyoung-Bae Kwon
• 정성균(Dept. of Mechanical and Automotive Engineering, Seoul National University of Science and Technology) | Seong-Kyun Cheong Corresponding Author