Reference values and improvement of aerodynamic drag in professional cyclists

Abstract

The aims of this study were to measure the aerodynamic drag in professional cyclists, to obtain aerodynamic drag reference values in static and effort positions, to improve the cyclists' aerodynamic drag by modifying their position and cycle equipment, and to evaluate the advantages and disadvantages of these modifications. The study was performed in a wind tunnel with five professional cyclists. Four positions were assessed with a time-trial bike and one position with a standard racing bike. In all positions, aerodynamic drag and kinematic variables were recorded. The drag area for the time-trial bike was 31% higher in the effort than static position, and lower than for the standard racing bike. Changes in the cyclists' position decreased the aerodynamic drag by 14%. The aero-helmet was not favourable for all cyclists. The reliability of aerodynamic drag measures in the wind tunnel was high (r > 0.96, coefficient of variation < 2%). In conclusion, we measured and improved the aerodynamic drag in professional cyclists. Our results were better than those of other researchers who did not assess aerodynamic drag during effort at race pace and who employed different wheels. The efficiency of the aero-helmet, and the validity, reliability, and sensitivity of the wind tunnel and aerodynamic field testing were addressed.

Riding against the wind: a review of competition cycling aerodynamics

“…Positions that resulted in reductions in aerodynamic drag were also related to a lower velocity deficit and turbulence levels in the wake. Studies by García-López et al [51] and Underwood et al [49] have shown that reducing the torso angle generally results in a reduction in aerodynamic drag. However, these studies also showed that minimising torso angle did not always lead to the lowest aerodynamic drag readings.…”

“…The effectiveness of rider equipment, such as bicycles and helmets, is also dependent on the position and type of rider [51,[63][64][65]. For these reasons, the most effective method to optimise a cyclist's aerodynamic performance to date has largely been through a trial-and-error approach to force measurements in a wind tunnel.…”

“…Another source of variation between wind tunnel investigations into rider position is differences in test methodologies and whether tests have been conducted with static or pedalling riders. The time-averaged drag force is not necessarily well represented by a static cyclist and significant variations in aerodynamic drag between static and pedalling cyclists have been reported [51]. Current research suggests that the drag coefficient of a pedalling cyclist is %6% higher than that of a static cyclist holding a horizontal crank position [12].…”

The Study of Details Effects in Cycling Aerodynamics: Comparison between Two Different Experimental Approaches.

“…Thus, due to the rather high velocity (in the order of 50 km/h), the aerodynamic resistance acting on a time-trial racer is about the 90% of the total resistance. Aerodynamics is thus very important for the cyclists performances and many experimental studies, addressed to find the best cyclist position as well as the best articles, have been carried out in the past (Garcia-Lopez et al, 2008;Gibertini & Grassi, 2008;Grappe et al, 1997;Lukes et al, 2005). Furthermore, although they are outside of the subject of the present treatise, some interesting computational works begin to appear in literature (see for example Defraeye et al (2010a;).…”

Aerodynamics Analysis for an Outdoor Road Cycling Helmet and Air Attack Helmet

“…Meanwhile common aerodynamic drag coefficient values for bicycles can range from 0.6 to 0.8 in racing configurations [5]. Previous research by field testing and wind-tunnel experiments by Garcia-Lopez et al [6] showed that adjustments to the cyclist's position, even minor ones, can result in a decrease of the aerodynamic drag, which indicates the possibility for optimization. In summary, previous research has shown that helmet aerodynamics can play a significant role in performance and that production helmets do not perform well at decreased pitch angles.…”