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CSME 2024/08
Volume 45 No.4
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329-336
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Mechanical Performances and Physiological Parameters for Cyclists Riding with Bi-ellipse Sprocket: A Cross-Field Study
Ardi Lesmawantoa, Soun-Cheng Wangb and Shinn-Liang Changa
aDepartment of Power Mechanical Engineering, National Formosa University, Yunlin, Taiwan 632301, ROC.
bDepartment of Athletic Sports, National Chung Cheng University, Minxiong, Taiwan 621301, ROC.
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Abstract:
The aim of this study is to compare the pedaling performances of a 32-tooth circular sprocket and four bi-ellipse sprockets with an increasing number of teeth (ranging from 33 to 36 teeth), where the maximum radius of the bi-ellipse sprocket is positioned at a 45-degree angle to the left crank. This comparison is conducted by evaluating both mechanical and physiological parameters. Nine recreational cyclists, with right-leg dominance and a minimum of one hour daily cycling over two years, participated in the study. Indoor tests with a constant cadence at 70, 80, and 90 rpm were performed to assess mechanical performance. Additionally, an incremental maximal test was performed, increasing by 30 watts every 2 minutes until exhaustion, to measure physiological parameters. These physiological parameters were used to confirm the observed mechanical performance. Results showed a significant increase in rear wheel speed with more sprocket teeth. While the 33-tooth sprocket exhibited the lowest peak and downstroke power, the 32-tooth sprocket showed no significant difference compared to the 34 and 35-tooth sprockets in mechanical parameter comparisons. Comparison of physiological parameters confirmed this, as they did not exhibit significant differences among the tested sprockets. This study provides valuable insights into how the number of teeth in sprockets affects pedaling performance, which is essential for cyclists looking to optimize their performance. Moreover, the research contributes to understanding the potential benefits of using bi-ellipse sprockets over circular sprockets in enhancing rear wheel speed and reducing peak and downstroke power during cycling.
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Keywords: noncircular sprocket, bi-ellipse shape, pedaling performance.
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*Corresponding author; e-mail:
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©
2024
CSME , ISSN 0257-9731
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