Calculate Your CdA in Minutes Using Notio

Do you want to find your coefficient of aerodynamic drag (CdA), to improve your cycling performances? With Notio, you don’t have to go to a velodrome or a wind tunnel anymore! You can calculate your CdA in just a few minutes.

 As a cyclist looking to increase your speed, the wind is one of the biggest elements you have to overcome. In fact, your efforts to gain speed and strength are in great part hampered by wind resistance: at 35 km per hour, about 80% of your energy is taken up fighting the wind. To improve your performance, you have to improve your aerodynamics. The first step is to determine your CdA to be able to measure your progress.

 Notio lets you determine your CdA easily, in an actual situation, without having to go to a velodrome or wind tunnel. The apparatus, attached to the handle bars and linked to a system of sensors attached to your cycle, measures various criterion that influence your aerodynamics. This data is transmitted to the Notio application which analyses it to provide your CdA.

Here is how to calculate your CdA.

1. Choose a Flat Terrain 

To calculate your CdA, find a flat terrain where you can carry out a road test for 3 to 4 km/ or minimum 5 minutes. The test can be on a country road, a long quiet street if the area allows it, or on a cycling path at a time when there is little vehicle traffic. 

Select a route free of obstacles and where car use is light. You’ll be able to avoid accelerations and decelerations and achieve your test with the utmost safety.

2. Ride at a Constant Speed

Choose a time when wind conditions are normal and wear your favourite cycling clothing. Go to the start of your testing route and start to ride in your usual riding position.

Ride for at least 3-4 km while maintaining as constant a speed as possible. Make a turn after 5 mins and or 3-4km and head back to your starting point for a distance of at least 6 km and minimum total time of 10min. It’s as simple as that!

3. Take Note of Your Result

Once you are stopped at the end of the test, the Notio app will tell you your CdA. This measurement applies only to you and your bicycle. Each cyclist receives a measurement that is unique and personal with reference to the various criterion of aerodynamics such as body shape, body position, helmet and clothing.

To provide a reliable measurement, the application compares the outbound and return portions of the test. It measures different factors such as speed variation, and makes calculations of the factors that affect your performance, to measure your aerodynamics. 

4. What to do if the test is rejected? 

When Notio can’t determine results reliably, test results are rejected. This happens when the application detects too large a disparity between the criteria on the outbound and inbound trips. This is an indication that one or more test conditions have not remained constant throughout the test.

  • Have you accelerated or slowed down too suddenly? If yes, restart the test avoiding sudden accelerations or decelerations.
  • Was the terrain flat enough? While riding up or riding down, the resistance due to gravity increases or diminishes, and this variation can skew the results.
  • Was the wind working against you? Several significant wind gusts or a lateral wind can affect the reliability of the result. If this happens, start the test again later when conditions are back to normal.

 5. Increase your Aerodynamic Effectiveness

Notio can help you find the optimal position to increase your aerodynamic effectiveness, while maintaining your ability to generate strength. Use the road test to evaluate the effects of different positions on your aerodynamics. For example by varying the angle of your hands and arms, and by changing the angle of your back, shoulders and head.

The aerodynamic coefficient will also help you make informed choices as far as equipment and clothing are concerned. Measuring your aerodynamics with different types of helmets and clothing will help you find the best combination for you. As far as your speed is concerned, different textiles and different clothing can have a major influence on your drag coefficient.

Finally, cycle accessories are an important factor in determining aerodynamics and the CdA can change depending on the type of accessories used and the possible combinations. A hydration system attached to the cycle or your body, for example, can influence aerodynamic effectiveness. 

You can also show your aerodynamic calculations to experts to have them analyze the results. They might help you to better position yourself. In short, by making your aerodynamic calculations available to you, Notio is providing you with a world of possibilities!