Cycling, Gear & Technology, Podcast

Bernardo Gonçalves | EP#397

 July 3, 2023

By  Bernardo Gonçalves


Bernardo Gonçalves - That Triathlon Show

Bernardo Gonçalves is an expert in aerodynamics and aerodynamic testing and optimisation, the founder of AeroEdge, and a pro continental cyclist. He is the person who has earned the trust to work directly with Scientific Triathlon pro triathletes on their aerodynamics. In this episode we discuss all things aerodynamics, and how triathletes of many different levels can improve their bike splits through aerodynamic optimisation. 

In this episode you'll learn about:

  • Quantifying and exemplifying the importance of aerodynamics
  • Why body position is by far the most important thing to optimise
  • Position changes that are often beneficial
  • Why more expensive bikes might not be any better than cheaper ones
  • A case for shorter cranks
  • Why track and road testing are the best ways of assessing aerodynamics for long distance triathletes (better than the wind tunnel)
  • Common mistakes in aerodynamic testing
  • Why W/CdA is much more important than W/kg
  • How to interpret marketing claims made by the cycling industry
  • Myths and misconceptions about aerodynamics and aero testing

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Bernardo's background

02:54 -

  • I'm Bernardo, a mechanical engineer and professional cyclist. 
  • I have a Master's degree in mechanical engineering from the University of Coimbra, focusing on evaluating and optimising aerodynamic drags. 
  • This led me to start AeroEdge, where I work with triathletes and cyclists to enhance their performance through aerodynamic testing, bike fitting, and preparation services.
  • As a professional cyclist, I race for the UCI Continental team X-Speed United. While I primarily compete at the continental level rather than the world tour, I have gained valuable experience racing in countries such as Portugal and Poland. I am also involved with the podcast Scientific Triathlon and Triathlon Show, where I write the show notes starting from episode 305. 
  • This role has given me a deeper understanding of topics related to physiology and other significant aspects discussed on the podcast.
  • With the podcast, I got a lot of insights into the world of triathlon, and this knowledge has further enriched my involvement in the podcast and my overall understanding of triathlon performance.

Quantifying the importance of aerodynamics

07:10 -

  • Aerodynamics is crucial in triathlon performance, directly affecting an athlete's efficiency and speed. By optimising the external forces that impede forward motion, such as aerodynamic drag, athletes can achieve greater efficiency and ultimately go faster for the same power output.
  • In the context of triathlon, the coefficient of drag area (CDA) is used to measure aerodynamic efficiency. 
  • Pro athletes competing in races like Kona typically have average CDAs ranging from 0.22 to 0.23 square meters, considering the factors of a full setup, movement, eating, and braking. 
  • However, beginner triathletes with standard equipment and a comfortable position may have higher CDAs, around 0.285 to 0.29 square meters for a 70-kilogram athlete.
  • Let's consider a 70-kilogram triathlete riding at 200 watts in Kona to put these numbers into perspective.
  •  With an average CDA, they could complete the course in approximately 5 to 5 hours and 3 minutes. 
  • However, by implementing an optimised pacing strategy and improving their setup and position, reducing their CDA to around 0.26 or 0.25 is possible. 
  • This simple adjustment could result in a 10 to 12 per cent percentage gain, translating to a time saving of around 10 minutes over the same course.
  • Through consistent training and belief in the work and recommendations, age-group triathletes can achieve professional-level efficiency in the long term. 
  • With a professional-level CDA, our example athlete riding at 200W could complete Kona in 4 hours and 43 minutes, saving 20 minutes compared to their initial performance.
  • These improvements in aerodynamics are not limited to Kona alone but can be applied to other racecourses as well. For instance, in Lanzarote, with a baseline CDA of 0.29, our example athlete could complete the full-distance race in approximately 2 hours and 47 minutes. 
  • With optimisation, they could save around 8 to 9 minutes. 
  • Even for shorter distances like the half-distance in Lanzarote, there are still considerable time gains to be made through aerodynamic optimisation.

The importance of body position

13:39 -

  • Regarding aerodynamics in cycling, the rider's body plays a significant role. 
  • From a frontal view, the body accounts for approximately 60 to 80% of the total aerodynamic drag, while the bike itself has a lesser impact, especially with the advanced integrated designs seen in modern bikes. 
  • Therefore, optimising the rider's position becomes crucial for maximising aerodynamic efficiency.
  • The gains from improving aerodynamics are becoming marginal in the cycling industry, where bike technology has reached a high optimisation level. 
  • The focus has shifted towards fitting the rider to the most optimal bike rather than vice versa. A higher-priced bike may not be faster if not tailored to the rider's position.
  • However, it's important to consider that optimising aerodynamics is just one aspect when working with athletes. 
  • Physiology, biomechanics, and the balance between aerodynamics and other factors come into play. 
  • The goals and type of event the athlete participates in must also be considered. 
  • The optimal position for a rider at different speeds, terrains, and event types can vary due to the external parameters they encounter.
  • A bike fit for a "perfect" position may not be realistic because the most optimal position for a rider at 40 kilometres per hour will differ from that at 20 or 60 kilometres per hour. 
  • Climbing and descending also require different positions due to mechanical considerations. 
  • Sprinting, for instance, is not performed in an aero tuck or on the aero bars due to mechanical inefficiencies.
  • Each athlete's unique biomechanics, physiology, and event requirements must be considered to strike a balance. 
  • Finding the fastest position that aligns with the rider's limitations and capacity for sustained efforts, fatigue resistance, and ability to maintain the prescribed position becomes a crucial aspect of optimising performance on the bike.

The relative importance of body position

17:13 -

  • Various factors, particularly the bike and body positioning, were highlighted in determining aerodynamic performance. 
  • When tested in a wind tunnel, the bike's coefficient of drag area (CDA) alone was found to range between 0.08 to 0.1 square meters. However, when riding upright, the combined CDA, which includes the body's contribution, increases to around 0.3 or 0.4. 
  • In contrast, adopting an aero position reduces the CDA to approximately 0.19, with the bike playing a more substantial role.
  • As athletes become more professional and efficient, the importance of having a fast bike becomes more pronounced. While optimising the body's aerodynamics is crucial, there is a limit to what can be achieved. 
  • For instance, some athletes, like Dan Bingham, claim a remarkably low CDA of 0.15, indicating that the bike's influence on total drag accounts for around 50% or 60%. 
  • Such levels of optimisation represent significant advancements in the field.
  • To provide a better understanding, let's consider a scenario where you are cycling at 40 kilometres per hour. At this speed, approximately 80 to 85%, or maybe even 90%, of your total power output, around 240 watts, would be required to overcome aerodynamic drag. 
  • Around 215 watts would be dedicated to overcoming the drag caused by the air resistance. 
  • Additionally, about 25 watts would be allocated to conquer rolling resistance, the resistance encountered from the road surface. 
  • Another 5 to 10 watts might be necessary to account for drivetrain efficiency, which refers to the power losses within the mechanical components of the bicycle's drivetrain.
  • It's important to note that these power distribution values may vary depending on external factors such as riding uphill or going downhill.

Commonalities that normally get you more efficient on the bike

20:10 -

  • Aerodynamics is complex, especially when dealing with human athletes and their bodies. 
  • The human body is not naturally streamlined, which makes optimising aerodynamics challenging. The parameter of interest is the drag coefficient (CD) multiplied by the frontal area. 
  • The body's shape influences CD and how streamlined it is. Studies have shown that the CD for various body positions typically falls between 0.6 and 0.7, while a cylinder-shaped object, like an upper arm, may have a CD of 1.2. 
  • In contrast, a streamlined body, such as an airfoil, could have a CD of around 0.04. 
  • This means that the drag produced by a cylinder is 24 times greater than that produced by an airfoil of the same size.
  • Two factors are considered to optimise aerodynamics: shaping the body to streamline it and reducing the frontal area. Software programs are used to adjust positions and decrease the frontal area, as this directly affects aerodynamic drag. 
  • A lower frontal area results in lower aerodynamic drag. Improvements in these parameters enhance efficiency and performance.
  • However, there are limitations to optimising aerodynamics. Extreme stretching to achieve a more streamlined body position can lead to injury, particularly for non-professional athletes lacking flexibility. 
  • Narrowing the body, such as by bringing the elbows closer together on TT extensions, may seem faster, but it depends on the individual's biomechanics and physiology. 
  • For athletes with broad shoulders, narrowing the elbows may actually increase the frontal area due to shoulder blade separation. 
  • Achieving the optimal balance is challenging and requires testing for individual athletes.
  • Working with human bodies and bluff bodies (objects with flow separation) is complicated because any change made to one part of the body can affect the flow around the rest of the body. Different setups, such as different equipment or skin suits, can also impact the effectiveness of specific changes. 
  • This complexity highlights the importance of individualised testing to determine the most effective aerodynamic setup.
  • One aspect agreed upon by aerodynamicists is the benefit of controlling the head position. Having the head between the shoulders and as low as possible reduces the frontal area, improving the CD and overall aerodynamics. 
  • This simple adjustment can lead to increased speed.

Setup changes to adopt a faster position

25:58 -

  • One of the challenges we face in bike fitting is dealing with bikes that limit our ability to optimise an athlete's position fully. 
  • Integrated cockpits, in particular, present difficulties as they restrict the range of motion and make it challenging to adjust the setup for optimal performance. 
  • Higher-priced bikes with built-in ergonomic extensions can further complicate finding an ideal position.
  • The cockpit itself also poses limitations. The placement of bottles and the need to accommodate hydration and spare equipment between the arms must be considered. 
  • These factors restrict the options for the optimising position. 
  • However, working with bikes without integrated cockpits has more possibilities, such as experimenting with longer reaches, different stems, and TT stacks.
  • Crank length is another area of interest and research. While there are studies on power output and crank length, there needs to be more research on fully utilising crank length to optimise efficiency and performance for specific events. 
  • Opening the hip angle improves power output, but applying this knowledge to different disciplines and events, such as climbing or time trials, requires further investigation.
  • Unfortunately, this area has limited research, but it is a crucial factor in generating power on the bike. 
  • Achieving the right balance between aerodynamics and power output is essential for maximising speed. 
  • Determining the ideal crank length for different events, such as uphill time trials or sprints, remains an important focus for us in bike fitting.

Crank length for triathletes

29:58 -

  • The choice of crank length depends on the athlete's goals, flexibility, and riding position. If a rider has a comfortable position with a high hip angle, crank length may not have a significant impact. 
  • However, there is a theory supported by anecdotal evidence that as the riding position becomes more aggressive, with a narrower hip angle, using shorter cranks can be beneficial for triathletes.
  • While some may argue that the size of the rider's body should determine crank length, it is not a straightforward relationship. For example, taller athletes may still benefit from using shorter cranks if they have an aggressive, aerodynamic position. 
  • The optimal crank length is not solely determined by body size but rather by the individual's position and ability to generate power efficiently.
  • Generally, using shorter cranks, typically in the 170-175 millimetres range, is often considered more advantageous for riders seeking an aggressive and aerodynamic position. As the riding position becomes more optimised, shorter crank lengths are believed to allow for increased power production based on available literature.
  • It is important to note that the relationship between crank length, body size, and performance is not linear and may vary for each individual. 
  • Therefore, a personalised approach considering the rider's position, flexibility, and performance goals is recommended when determining the most suitable crank length.
  • When considering the optimal crank length for riders, it is important to focus on angles rather than leg length. 
  • Riders may have varying leg lengths due to differences in body proportions, such as longer legs and torsos or longer upper legs and quads. 
  • Therefore, it is more practical to base studies and recommendations on angles that can be replicated with every athlete.
  • For instance, athletes with significant height differences, ranging from around 1.60 meters to 1.90 meters, may still be advised to use the same crank length despite their discrepancies in size. 
  • This is because the recommended crank length considers the individual's desired position and riding style. 
  • An athlete with a smaller height may have a more comfortable position, while a taller athlete may adopt a more aggressive and speed-focused riding style.

Run off-the-bike considerations

33:44 -

  • One of the primary concerns when working with athletes in triathlon is their ability to run effectively after cycling. 
  • It is crucial to balance optimising aerodynamics on the bike and ensuring the athlete's ability to perform well in the run. 
  • While advantageous for speed, aggressive bike positions can increase recruitment in the glutes, quads, and lower back, potentially compromising the athlete's running capabilities.
  • To mitigate this risk, it is essential to be mindful of an athlete's limitations and avoid making abrupt or extreme changes to their position. 
  • Instead, taking a longer-term approach is advisable. 
  • Conducting a mobility analysis can help identify any limitations and address them before progressing to more aggressive positions. 
  • The goal is to ensure that the athlete has the necessary mobility to maintain a specific position without risking injury.
  • A compromise is often necessary, but with a longer-term plan, it is possible to work on these limitations and gradually transition to more efficient and faster positions. 
  • By adopting positive positions and optimising aerodynamics, athletes can save energy and potentially reduce power output while maintaining the same speed. 
  • This approach ultimately enhances their performance in the run segment, aiming for a personal best.
  • While achieving a faster bike split is a primary objective, the ultimate goal is to excel in both the bike and run segments. 
  • By striking the right balance and addressing limitations, athletes can improve their aerodynamics and achieve faster run times by conserving energy during the bike leg. 
  • This approach has already yielded successful outcomes for athletes who have implemented it.

Testing methods

36:20 -

  • At AeroEdge, we primarily rely on field testing for our evaluations. The availability of aerometers and modelling tools has made it possible to quantify positional changes. 
  • While wind tunnel testing and computational fluid dynamics (CFD) have their merits, I believe that cycling and triathlon will follow a similar path to motorsports like F1.
  • In motorsports, teams utilise wind tunnels and CFD for research and product development, but they ultimately validate the results on the tracks. Similarly, achieving the fastest position in a wind tunnel is irrelevant if it cannot be replicated on the road. 
  • It renders the money spent on wind tunnel testing worthless. However, wind tunnels still have their place. 
  • They allow us to optimise other aspects, such as comparing wheel performance or testing tri-suits. 
  • The controlled environment of a wind tunnel or using CFD provides greater accuracy and understanding of optimal conditions for specific athletes or speeds.
  • Field testing holds greater importance for us as our goal is to help athletes go faster and maintain that speed for extended periods, such as four hours. 
  • It only makes sense to test and make adjustments within the actual riding conditions. 
  • The test results will be positive if athletes sustain those positions and changes. If they struggle to hold the positions, the test becomes inconclusive.

Field Testing protocols

39:15 -

  • Our field testing protocols involve aerometers and are tailored to the specific needs and goals of the athletes we work with. 
  • When approached by an athlete, we gather information about their objectives, motivations, injuries, and equipment to better understand their circumstances and design protocols accordingly.
  • For triathletes, we consider the limitations discussed earlier, aiming to create protocols that influence their positioning without compromising their ability to perform well in a run off the bike. 
  • Typically, we recommend a long-term program that spans several months, with multiple monthly sessions, to validate and assess the results obtained from each testing phase.
  • Field testing presents challenges in terms of accuracy and reliability. To ensure precise measurements, we conduct numerous repetitions using different protocols, including longer ones. 
  • This extensive testing requires endurance and dedication. 
  • We aim to deliver conclusive and reliable results to the athletes who work with us, avoiding inconclusive or inaccurate conclusions that could misguide their training efforts.
  • Our field testing protocols are designed to provide accurate and meaningful data by carefully tailoring the testing process to the individual athlete's needs and conducting thorough repetitions and analyses to validate the results.

The benefits of field testing

43:19 -

  • It's crucial to acknowledge the uncertainties associated with the results when presenting data, which, unfortunately, is not always done comprehensively in the literature.
  • One specific issue is the lack of reporting uncertainty associated with measured values. 
  • For example, in wind tunnel testing, the coefficient of drag (CDA) is often presented as a single value without the corresponding uncertainty. 
  • However, when measuring CDA over a certain period and averaging the data, inherent uncertainty is associated with that value. 
  • Wind tunnels typically have an error range of 1.5% to 2.5%, which means that the reported CDA value should be presented as, for instance, 0.2 plus or minus 0.005.
  • This discrepancy can be frustrating, as claims about minute differences in performance may not be statistically significant when considering the associated uncertainties. 
  • It's important to understand that these measurements are averages; even wind tunnel testing may not provide greater accuracy than field testing. 
  • In field testing, although there is more variability due to position changes, you can at least experience the actual conditions and observe immediate performance differences.
  • A crucial aspect to consider is the practicality and sustainability of a given position or setup. 
  • For example, a position that appears aerodynamically optimal in a wind tunnel may not be sustainable during an actual road ride. 
  • Factors such as maintaining a clear line of sight and comfort over long distances come into play. 
  • It's not solely about achieving the fastest possible setup but rather finding a balance between aerodynamics and a position that can be maintained for the required distance. 
  • If the position is both the fastest and sustainable, it can improve run performance, creating a win-win situation.
  • By considering these factors and understanding the limitations of testing methods, researchers and athletes can strive for more meaningful and applicable findings in the pursuit of optimal performance.

Mathematical models

48:00 -

  • Aerometers are equipment that consists of sensors and software used to gather and analyse data related to aerodynamics. 
  • The sensors capture temperature, wind speed, power, cadence, wheel data, and ground speed. 
  • This data is then processed using mathematical models to calculate the coefficient of drag (CDA). 
  • The models can be created using tools like Excel or Matlab.
  • The advantage of using aerometers is that they are based on physical models, which are reliable and grounded in physics principles. 
  • These models consider variables like speed and elevation to determine CDA in different scenarios. 
  • Choosing the most appropriate model for each athlete is important based on the specific protocol and environment they are working in. 
  • For example, a model used for a cyclist in a velodrome may differ from one used for a cyclist on the road, where aerodynamics plays a more significant role.
  • By working with these models, baseline data can be established, allowing for accurate performance analysis and prediction. 
  • Coaches can manipulate course conditions and estimate how variable changes impact an athlete's performance. 
  • This provides valuable insights into an athlete's progress and improvement.
  • The benefit of using these models is that once baseline data is established, remote monitoring and analysis become possible, yielding comparable results to an actual aerometer. 
  • This enables coaches and athletes to assess performance and adjust even when direct access to the aerodynamic measurement equipment is unavailable.
  • Regarding using sensors and equipment for aerodynamic testing, calibration is crucial. 
  • Ensuring accurate calibration is challenging, especially with devices like the Notio or Aerolab sensor, as the airflow around the body can affect the recorded wind speed. 
  • Calibration procedures attempt to estimate the true wind speed, but discrepancies can occur. For instance, an aerometer might indicate a headwind of one kilometre per hour when it could be three or four kilometres per hour.
  • The issue lies in the variability of calibration factors. Different runs may yield different calibration values, leading to uncertainty about which value to choose. This is where models play a significant role. 
  • One can analyse and determine which calibration factors make the most sense by employing models. This analysis provides a more accurate estimation of speed and, consequently, the coefficient of drag (CDA) or aerodynamic efficiency.
  • Models allow a more refined and approximate measurement of the recorded speed, enabling a more precise assessment of an athlete's aerodynamic performance. By considering the concrete results and the closest approximation of actual speed, the CDA or aerodynamic efficiency can be better evaluated.

Common aero testing mistakes

53:59 -

  • When assessing aerodynamic performance and making improvements, it is important to approach the process with realistic expectations and caution. Instantaneous results or live coefficient of drag (CDA) values should not be taken at face value. 
  • Many devices, like aerometers or the Notio, may provide immediate average CDA values, but these numbers can often be arbitrary and require careful interpretation.
  • Ensuring that the testing protocols being used are accurate and consistent is crucial. 
  • Not all protocols available in the market are reliable, and selecting ones that provide meaningful and actionable data is necessary. 
  • The way sensors and aerometers work can introduce biases or data selection issues, as average values are typically measured during CDA assessments, requiring data sampling. 
  • Inaccurate testing procedures can lead to high random variability and uncertainty in the resulting CDA values.
  • To avoid biased interpretations, it is important to be critical of claims that promise significant CDA improvements without corresponding increases in speed at the same power output. If someone claims a 10% improvement in CDA, but your speed hasn't increased by 1.5 kilometres per hour, it's unlikely that the improvement is truly 10%. 
  • Be aware that biases can easily influence results. I could tell athletes that any setup or testing procedure leads to improvement if I wanted to. 
  • That's why using models and relying on companies like AeroEdge is valuable. 
  • Models help minimise biases; the ultimate goal is to help athletes ride faster.
  • Providing athletes with accurate and informative feedback is essential. 
  • If a setup or approach does not yield faster results, it's important to acknowledge that and explore alternative directions. 
  • Transparency and reliable data are key in guiding athletes towards effective improvements in aerodynamic performance.

Aero optimisation case study

57:28 -

  • I worked closely with Luis Moleiro, an age-group triathlete, who became a case study for AeroEdge. 
  • Recognising his potential, I approached him when I launched the company, offering him the chance to be one of my first clients. Evidently, there were areas where we could significantly improve his performance.
  • Over six months, Luis diligently followed our procedures and embraced the importance of aerodynamic efficiency. 
  • Through testing and adjustments to his positions, we improved his coefficient of drag (CDA) by nearly 20 per cent. A notable race where these improvements were evident was the Setubal Triathlon in Portugal, similar to a 70.3 event.
  • In the previous year, Luis completed the cycling segment in two hours and 28 minutes. 
  • However, with the adaptations and improvements we had made this year, he achieved a time of two hours and 20 minutes. 
  • Remarkably, his power output was 20 watts lower than the previous year, yet he managed to ride 2.5 kilometres faster. It was a testament to the impact of optimising aerodynamics on performance.
  • Despite feeling slightly less fit than the previous year, Luis approached the race with some apprehension about his performance. 
  • I deliberately underestimated his expected splits or average speed to provide added confidence, ensuring he would surpass the target. It's always preferable for an athlete to exceed expectations and achieve their goals.
  • Ultimately, Luis surpassed his target time and achieved a personal best in the half marathon segment of the race.
  • During the optimisation process, we focused primarily on the athlete's position, specifically the cockpit and saddle positions. We achieved significant gains by making adjustments to these areas, such as changing the reach stack and wheels (from tubular to a more suitable option). 
  • Approximately 12% of the overall 20% improvement was directly attributed to the optimised position.
  • It's worth noting that the athlete was not using an expensive bike. Instead, he rode a standard Canyon bike valued at around €3,500. However, this presented an opportunity for us to make cost-effective improvements. We achieved substantial performance enhancements by strategically investing in equipment upgrades without excessive financial burden.
  • One of the advantages of this work is that, if approached intelligently, it is possible to balance the investment and potential gains. While there may be a point where further marginal gains require significant investment, in this case, we were able to leverage smart investments to achieve significant improvements.
  • The athlete sold some of their existing equipment to fund the purchase of more performance-oriented gear, resulting in a net gain without excessive spending.

Top 3 product/service purchases related to aerodynamics

1:03:14 -

  • In my biased opinion, seeking expert guidance, such as AeroEdge, is crucial when considering upgrades to improve aerodynamics.
  • Someone knowledgeable in the field can provide valuable insights and help make informed investment decisions. It's important to avoid falling for marketing claims and instead rely on research and the expertise of professionals.
  • Investing in equipment that enhances position flexibility is another key aspect.
  • This includes bike fitting, adjusting the cockpit, and incorporating elements like angled spacers and stacks to optimise the rider's position.
  • Adaptable equipment is particularly valuable for triathletes who need to conform to specific regulations while maintaining an optimal position.
  • For triathletes, prioritising hydration and nutrition is vital. No matter how fast the bike is, performance can suffer if access to nutrition is compromised during races.
  • Ensuring easy access to hydration and nutrition during long-distance events like an Ironman is crucial for maintaining energy levels and maximising performance.
  • These three areas—expert guidance, equipment optimisation for the position, and prioritising hydration and nutrition—are the primary considerations when seeking upgrades.
  • Once these fundamentals are addressed, other aspects can be explored, but these three factors lay the foundation for performance improvement.

Bernardo's favourite products upgrades on his bike setup

1:07:07 -

  • When it comes to optimising my bike setup, several key components play a significant role.
  • The first is the cranks, which completely change the way I ride. Another crucial element is the handlebars, particularly for road biking.
  • My setup is considered quite extreme, and it has worked well for me despite not being naturally gifted athletically. I focused on optimising my handlebar position to enhance my performance.
  • The saddle is another critical aspect that should not be overlooked. Saddle sores, especially in female athletes, can be challenging to manage and evaluate.
  • Companies like Giobiomized have done excellent work in addressing this issue by considering saddle position and individual fit. Each person's optimal saddle will be different, so finding what works best for oneself is essential. Saddles like the ISM PN 3.0 have effectively alleviated saddle sore problems I have struggled with for years.
  • Handlebar width is also worth considering. Due to UCI restrictions, I previously had a standard 32 centre-to-centre handlebar.
  • However, I recently switched to the AeroCoach Ornix handlebars, which I've used in races for a few weeks.
  • While they look amazing, there is a slight limitation in optimising the setup because the handlebars are more suitable for electronic gear systems. Nonetheless, their aerodynamic design is impressive, as is often the case with the most efficient and visually appealing equipment.

W/CdA vs W/kg

1:10:25 -

  • I've had extensive discussions with Michael regarding this topic, as we've collaborated on scientific Triathlon projects together.
  • One area of focus has been analysing data from last year's Kona race to explore correlations between performance and parameters such as watts per kilo, watts per CDA, and absolute power.
  • When examining the correlation between watts per kilo and speed, we found a relatively weak correlation of 0.3 based on the Pearson correlation factor.
  • This suggests that there is no strong relationship between Kona performance and watts per kilo. For example, athletes with the same watts per kilo could achieve significantly different finishing times.
  • In contrast, as expected, the correlation between absolute power and speed was higher, at 0.6.
  • The more power an athlete produces, the faster they go, which is a straightforward relationship. Additionally, we looked at the watts per CDA value and discovered a strong correlation factor of 0.956. This indicates that watts per CDA are a powerful performance indicator. It is a better parameter to assess an athlete's performance than watts per kilo.
  • Watts per CDA allows us to account for differences in power meters and mitigate measurement errors. By dividing power by CDA, we obtain a parameter that aligns with performance expectations.
  • Using watts per CDA, we can accurately compare athletes and assess their performance relative to others.
  • It provides insights into how athletes compare to their competitors and what they must do to achieve a winning result. 
  • This analysis emphasises the importance of watts per CDA over watts per kilo in understanding performance.
  • It's worth noting that weight biases are prevalent in triathlon and cycling, particularly due to terrain considerations. However, this analysis demonstrates that the correlation between performance and watts per kilo is not as significant as commonly believed.
  • Weight is a tangible factor that can be perceived, unlike the coefficient of drag (CDA).
  • However, speed is a perceptible element that can be immediately felt during field testing. Athletes can sense whether they are faster or slower and provide accurate feedback on their performance.
  • When athletes express a feeling of increased speed, it often aligns with the data collected, confirming the validity of the results. In remote testing, it is important to acknowledge that aerodynamics and testing for speed have been conducted for many years. Aero testing has a long history, with methods such as downhill testing and intuitive comparisons between different setups.
  • However, today's key distinction lies in our ability to quantify and analyse the differences with the help of models and specialised equipment. 
  • This allows for a more precise assessment of aerodynamic performance and its correlation with overall athletic performance.

Speed as the key metric for performance

1:17:34 -

  • Speed is a crucial factor that should not be overlooked when conducting field testing.
  • While certain test providers may provide biased or inaccurate data, the ability to measure and observe speed on a computer can act as a valuable safeguard.
  • Speed is the tangible outcome athletes experience during transitions, ultimately determining their performance.
  • Understanding the desired speed necessary to achieve specific time or position goals is essential for athletes.
  • This knowledge allows them to set appropriate targets and work towards achieving optimal results.
  • While power has gained significant focus in triathlon cycling over the years, it is important to remember that speed ultimately wins races.
  • In my experience, when athletes approach me for testing, I emphasise the importance of carefully considering power meter readings.
  • It is not uncommon for athletes to claim they are sustaining high power outputs, such as 300 watts for two hours, yet their actual speed does not align with those numbers.
  • Conducting a calibration procedure for their power meters is typically the first step to ensure accuracy.
  • Ultimately, the athlete who achieves the highest speed, rather than simply generating more power, is the one who succeeds in bike races and triathlons.
  • Therefore, the primary goal should always be to strive for maximum speed and optimise performance during such endeavours.

Myths and Misconceptions about aerodynamics

1:18:35 -

  • There are several important points to address regarding the use of aerometers and the misconceptions surrounding them. Firstly, simply having an aerometer does not guarantee accurate and reliable data.
  • It is crucial to consider various factors carefully during the testing process.
  • For instance, temperature fluctuations can significantly impact rolling resistance, which affects speed measurements. Aerometers typically measure air density but do not account for changes in rolling resistance due to temperature.
  • Additionally, sensor accuracy can be influenced by factors such as exposure to sunlight and radiation, leading to potential errors in temperature measurements and subsequent air density calculations.
  • Analysing the data post-test using software like Golden Cheetah can help identify erroneous or fluctuating air density values, which can render the data unreliable.
  • Without accounting for these factors and conducting a thorough post-analysis, it becomes challenging to determine accurate results, making it difficult to discern improvements or differences in speed and efficiency.
  • Another misconception is placing too much emphasis on isolated variables like power and coefficient of drag (CDA) while neglecting other crucial factors. In reality, measuring aerodynamics involves considering multiple variables simultaneously and ensuring they fall within an acceptable margin of error for meaningful statistical differences.
  • This task is challenging to achieve.
  • Believing claims made by manufacturers without considering the exponential nature of aerodynamic drag is another common misconception.
  • A claim that something is three watts faster at 55 km/h may not hold much significance as it represents a smaller percentage gain in terms of power savings compared to a claim of three watts faster at 30 km/h.
  • The CDA savings at higher speeds are typically within the margin of error of wind tunnel testing, which may indicate inaccuracies or biases in the results.
  • Lastly, assuming that a particular tri-suit or skinsuit will be faster based on its performance on another athlete is a fallacy. The effectiveness of these garments depends on individual body characteristics, riding speed, and position.
  • Personal experiences, like the example of a costly trisuit that turned out to be slower than traditional bibs and jerseys for the individual, highlight the importance of testing before making significant investments in aerodynamic clothing.
  • Various equipment, including calf cards, socks, overshoes, and helmets, can impact aerodynamics differently for each person, and assumptions of universal speed gains may not hold true.

Testing optimisation process

1:25:45 -

  • When optimising aerodynamics in sports, the initial focus should be on the athlete's position. Finding a position that enhances the body's shape in the frontal area.
  • This entails achieving an optimal position that can be sustained over a prolonged period.
  • Once the ideal position is established, attention can be directed towards evaluating and optimising other equipment, such as cockpits and wheels.
  • However, it is important to emphasise that position always precedes equipment choices.
  • Prioritising equipment testing, such as wheels and skin suits, without first addressing the athlete's position may lead to misguided outcomes.

Rapid-Fire Questions

1:26:39 -
What's your favourite book or resource related to endurance sports?
I'm an avid listener of podcasts.
There's an excellent podcast called Endurance Innovation with Michael Liberzon and Andrew Bucknell.
The Physical Performance Show with Brad Beer 

What's an important habit you've benefited from athletically, professionally or personally?
First, being consistent. Being consistent with everything that I do helped me to get to the point that I can dream of achieving a dream.
Having the discipline to continue putting in the work, accepting the process and sticking with it for a period to ensure that we can get something out of it.
And self-reflection, spending some time thinking of what I do and trying to fine-tune everything I do and improve. I want to ensure that I can continue learning and keep humble.

Who's somebody that you look up to or that has inspired you?
I've known Michael for a long time, and he has become a mentor and a friend. Working with Scientific Triathlon allowed me to learn and gain autonomy to do things differently, which led me to develop AeroEdge. 


Bernardo Gonçalves

Bernardo is a Portuguese elite cyclist and co-founder of SpeedEdge Performance, a company focused on optimising cycling and triathlon performance. He writes the shownotes for That Triathlon Show, and also produces social media content for each new episode.

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