Aerodynamic Optimisation

by Lorenzo Bordino

In competitive cycling, reducing aerodynamic drag is one of the most effective ways to improve performance. While increasing power output is challenging and requires years of training, reducing drag can yield significant speed gains with relatively simple adjustments. From apparel choices to positional refinements, each small change contributes to substantial overall savings in wattage. But how much do these optimizations really matter? This article examines key aerodynamic improvements and their respective power savings at 45km/h and a 0° yaw angle.

The Role of Aerodynamics in Cycling

Aerodynamics plays a crucial role in cycling efficiency. At high speeds, more than 80% of a rider’s power output is used to overcome air resistance. Therefore, any reduction in drag translates directly into a higher speed for the same power expenditure. Let’s analyse different aerodynamic upgrades and their impact.

1. Aero Shoe Covers

Aero shoe covers help smooth airflow around the shoes, an area prone to turbulence due to the movement of the pedals.

• Power savings: 3-6 W
  
• Benefit: Reduced drag by minimizing turbulence around the feet.
  

2. Aerodynamic Base Layer

An aerodynamic base layer with textured fabrics can enhance airflow over the torso, reducing drag compared to a standard jersey or bare skin.

• Power savings: 8-12 W
  
• Benefit: Improved airflow over the upper body, which is a key area of aerodynamic resistance.
  

3. Aero Helmet

The helmet is one of the most critical aerodynamic components since the head is constantly exposed to airflow.

• Power savings: 10-15 W
  
• Benefit: Reduced frontal drag and optimised airflow over the shoulders.
  

4. Narrow Handlebars (40cm to 36cm)

A narrower handlebar reduces the rider’s frontal surface area, making them more streamlined. Flared handlebars have also become popular (and tuned-in shifters) for improved aerodynamics as well as improved control.

• Power savings: 5-10 W
  
• Benefit: Lower drag due to a more compact frontal area.
  

5. Aggressive Aero Position

One of the most significant factors in aerodynamic efficiency is body positioning. A more aggressive aero position, with a lower torso and narrower arm placement, significantly reduces frontal drag.

• Power savings: 20-30 W
  
• Benefit: Improved overall aerodynamic efficiency but requires flexibility and core strength.
  

6. Aero Chainring vs. Standard Chainring

Aero chainrings reduce turbulence around the crank area by covering gaps and smoothing airflow.

• Power savings: 2-5 W
• Benefit: Minor but noticeable reduction in drag from drivetrain components.

Summary of Aerodynamic Gains

Aerodynamic Upgrade	Power Savings (Min)	Power Savings (Max)
Aero Shoe Covers	3 W	6 W
Aerodynamic Base Layer	8 W	12 W
Aero Helmet	10 W	15 W
Narrow Handlebars	5 W	10 W
Aggressive Aero Position	20 W	30 W
Aero Chainring	2 W	5 W
Total Savings	48 W	78 W

The Overall Impact

The combined effect of these optimisations results in a power saving ranging from 48W to 78W at 45 km/h. Given that sustaining this speed typically requires 350-400W, these savings equate to a 12-20% improvement in efficiency. This means that a rider maintaining 400W with a non-optimised setup could achieve the same speed at only 322-352W with these enhancements, a significant competitive advantage.

Practical Considerations

While each upgrade provides tangible benefits, their effectiveness depends on factors such as rider position, bike fit, and individual biomechanics. Some changes, like adopting a more aggressive aero position, may require adaptation and flexibility training. Others, such as using an aero helmet or shoe covers, offer immediate advantages with no downside.

Note on wheels

Aero wheels offer additional aerodynamic advantages that are beyond the scope of this list. High profile rims minimise aerodynamic drag, especially at high speeds and on flat roads. This upgrade can further increase overall speed and efficiency, and will be explored fully in a future article of Road-Cyclist's Handbook.

Conclusion

Optimising aerodynamics is one of the most effective ways to improve cycling performance. Small changes can lead to substantial power savings over a longer period, making a noticeable difference in speed, efficiency and endurance. Whether you are a time trial specialist, a road racer, or an endurance rider, focusing on aerodynamics can provide free speed and improve your overall cycling experience. By implementing these adjustments, cyclists can maximize their potential and ride faster with less effort.