How and Why to improve aero position on bike
All cyclists struggle to find their best aero position while training or competing. Let’s see why they should strive to improve aero position on bikes for better cycling performance!
Why? Because the rider’s body mass generates the biggest amount of “drag”, or wind resistance, that is going to affect the speed and power consumption during the course of a ride. Measurements indicate that over 16km/hour on a flat road, the wind is inarguably a Cyclist’s biggest opponent.
• At 29 km/hour it becomes 80% of the resistance
• At 40 km/hour it becomes 90% of the dominant force
Recent studies conclude that minimizing aerodynamic resistance by “fine-tuning” the rider’s position is the most effective way to improve performance if an athlete is already well-trained and improvement in power and stamina is not happening as short term as for a beginner.
We see athletes trying to find the best aerodynamic position, using the technology available, the last two decades, but the last ten years industry is really focusing on the subject due to its top priority in the professional level.
Graeme Obree was the first athlete to try different positions on his bike than what was used to ride in general, to gain the maximum aerodynamic advantage, and managed to break the prestigious world hour record (1993 and 1994) twice in his career.
Chris Boardman followed breaking the world hour record three times with his new aero position, known as the “superman position”.
Today all athletes are working on their own unique aerodynamic position that best suits their body type and discipline.
How to improve aero position
Aerodynamic resistance plays a major role in determining how fast we can go on our bikes. So, how much air resistance can we “push” moving forward and how fast, at what speed is the limit where our power will equalize against air resistance?
How much, so is a matter of an object’s (that’s the athlete’s) drag coefficient (Cd) and its frontal area (A)?
The effective frontal area is the most important parameter that affects aerodynamic drag. Multiplied together, Cd-A gives a factor of aerodynamics.
The higher this figure, the harder we must work to fight air pressure and maintain speed. So, the bigger the object is, the bigger its frontal area and the higher its CdA factor.
CdA estimation techniques are now well recognized in cycling, and this parameter can be evaluated in a laboratory or in the field with great reliability.
However, although the projected frontal area is easily quantifiable, the variation in the drag coefficient is more complex. Its evolution according to the speed of movement is not yet fully controlled.
More research is needed to study its variations, new methods such as computational fluid mechanics could help.
Comfort vs Efficiency in Cycling
The aerodynamic position is not always the most comfortable position, but it is the one that allows the production of optimal power and pedaling cadence.
During a race, comfort must be taken into account together with optimum aero position, the combination of the two will allow the athlete to have the best performance. The longer the duration of the race is, the more of a factor, comfort becomes.
Everything will depend on the joint mobility and flexibility of cyclists. An athlete must be comfortable but also aero, in a position that can maintain for almost all the duration of the race.
By Demetra Michaelide
BSc in Sport Science
UCI Level II Certified Cycling Coach