[Research Review] Aerodynamic and Rolling Resistance Report on Carbon Wheelsets of Different Rim Depths Under Various Yaw Angles: A Study of Elite Athlete Physiological Characteristics (No. 77)

Source Journal Reference: Journal of Wind Engineering and Industrial Aerodynamics • International Scientific Research Findings Review Series

This article explores the aerodynamic and rolling resistance characteristics of carbon wheelsets with different rim depths under various yaw angles.

The Trade-off Between Rim Depth and Crosswind Sensitivity

The deeper the rim, the more pronounced the aerodynamic drag savings when riding directly into the wind or at small yaw angles, as the deeper profile more effectively guides airflow and reduces vortex separation. However, a deeper rim also means a larger side surface area exposed to the wind. At larger yaw angles (particularly in the 15–20 degree range), deep-section wheels endure greater lateral moments, which correspondingly raises the challenge of handling stability.

Yaw Angle and Wheelset Handling Comparison

Modern wheelset designs have utilized “NACA-like” airfoil profiles to optimize performance, allowing deep-section wheels to generate a “sail thrust” effect at moderate yaw angles (due to delayed flow separation). However, once the yaw angle exceeds a certain critical threshold, the lateral moment still rises sharply—this is the physical reason why deep-section wheels become more challenging to ride in strong crosswind conditions.

Comparison of Drag and Lateral Moment Across Different Rim Depths (Illustrative)

Core Research Conclusions and Practical Recommendations

• Race Day Weather Assessment: Check the day’s wind direction and speed forecast before racing. When strong crosswinds are expected, the handling stability advantage of shallow or mid-depth wheels often outweighs the drag savings of deep-section wheels.
• Front/Rear Wheel Pairing Strategy: The front wheel’s exposure to crosswind moments has a more direct impact on handling. A common strategy is to use a shallower rim on the front and a deeper rim on the rear, balancing handling and aerodynamic efficiency.
• Rider Weight and Handling Skill Considerations: Lighter riders or those with less handling experience face relatively higher risk when using deep-section wheels in strong crosswinds and should opt for more conservative choices.
• Don’t Overlook Rolling Resistance: Beyond the discussion of rim depth and aerodynamic drag, the rolling resistance of the tires and wheelset itself also affects overall efficiency. Decisions should not be based solely on rim depth figures.

Common Research Q&A (FAQ)

Q: Are deep-section wheels absolutely faster in a completely windless time trial?

A: In an ideal straight-line time trial scenario with no crosswind, the drag-saving benefits of deep-section wheels are indeed more pronounced. However, real race conditions rarely feature absolutely no wind, so the day’s wind conditions still need to be considered comprehensively.

Q: Do average amateur riders need to buy deep-section wheels?

A: The benefits of deep-section wheels only become clearly apparent in high-speed, long-straight-line scenarios. If your riding primarily involves climbing, urban commuting, or varied terrain, mid-depth or shallow wheels are typically more practical.

References and Academic Citations

1. Journal of Wind Engineering and Industrial Aerodynamics — Research direction on crosswind aerodynamics of bicycle wheelsets.
2. Sports Engineering — Literature on the interaction between wheelset rim depth and rolling resistance.

Related Reading

• 【科研導讀】不同框高碳纖維輪組在不同側風偏角下的空氣動力學與滾阻阻力報告：頂尖選手體能特徵研究 (第 425 篇)
• 【科研導讀】不同框高碳纖維輪組在不同側風偏角下的空氣動力學與滾阻阻力報告：頂尖選手體能特徵研究 (第 1292 篇)
• 【科研導讀】不同框高碳纖維輪組在不同側風偏角下的空氣動力學與滾阻阻力報告：頂尖選手體能特徵研究 (第 161 篇)
• 【科研導讀】不同框高碳纖維輪組在不同側風偏角下的空氣動力學與滾阻阻力報告：頂尖選手體能特徵研究 (第 209 篇)