Reference Values and Improvement of Aerodynamic Drag in Professional Cyclists
Five professional cyclists were measured in a wind tunnel in four positions on a time-trial bike and one on a standard road bike, both static and while pedalling at race pace. On the time-trial bike the drag area was 31% higher while pedalling ("effort") than in the static position, and it was lower than on the standard racing bike.
Changing the riders' positions reduced aerodynamic drag by 14%, the aero helmet did not help every rider, and repeat measurements in the tunnel were highly reliable (r > 0.96, coefficient of variation < 2%).
Participants
n=5 professional cyclists (abstract: "five professional cyclists"). Sex, age and body size are not given in the abstract.
Protocol
Wind tunnel; four positions on a time-trial bike and one position on a standard racing bike.
Aerodynamic drag and kinematic variables recorded in all positions, in static and effort (pedalling at race pace) conditions.
Position and equipment (including an aero helmet) modified to reduce drag; reliability of the tunnel measurement assessed.
Key Results
Drag area on the time-trial bike was 31% higher in the effort position than in the static position, and lower than on the standard racing bike.
Changes in the cyclists' position decreased aerodynamic drag by 14%.
The aero helmet was not favourable for all cyclists.
Reliability of the wind-tunnel drag measurement: r > 0.96, coefficient of variation < 2%.
The authors state their drag values were better than those of researchers who did not measure drag while pedalling at race pace and who used different wheels; the absolute values are not in the abstract.
Practical Application
In a wind tunnel with five professional cyclists, changing position cut aerodynamic drag by 14%, drag area while pedalling at race pace was 31% higher than in a static pose on the same time-trial bike, and the aero helmet did not help every rider. A position judged standing still underestimates the drag you race with, so check a TT position while pedalling at race effort.
Test the helmet on the rider, not by reputation: in this group it was not favourable for all.
The abstract gives no absolute drag-area (CdA) values; do not quote a reference CdA from this entry.
Inference, not tested here: a measurement error below 2% means position changes smaller than that could not be told apart in this tunnel; a home field test is likely noisier.
Inference, not tested here: the 14% came from refining professionals' positions; how much an amateur gains depends on how far their starting position is from a good one.
Limitations
n=5 professionals; sex, anthropometry and individual values are not in the abstract.
Wind tunnel only; no road or field measurement and no time-trial performance outcome.
Results are relative (percent changes); the reference drag values promised in the title are in the full paper, not the abstract.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level
small measurement series, n=5 professional cyclists