One of the season’s hottest topics and something everyone will be looking at during the next three weeks is the Ironman World Championship in Kailua-Kona. A topic that you find in every triathlon magazine worldwide and one more reason for us at Aerotune to take a closer look at the 180 kilometer bike split segment of the season’s biggest race. To predict the possible outcome for Kona 2017, we took data of some Pro Athletes, which we gathered on Trainingpeaks and Strava and inserted them into our aeroCAST tool. We took some assumptions on the total system weight and the Crr value (rolling resistance) in regards to the used material of the athletes. Generally, our aeroCAST tool is used to help athletes predict and tactically optimize their bike leg of a specific race; based on the measured CdA value of the aeroTEST and the planed power output. In this case, we did a reverse calculation by using known power, time and weather data and did a calculation of the CdA the athlete must have had during the Ironman 2016 race.

With Jordan Rapp, we have already carried out our aeroTEST ourselves (read the blog post). Because of this, we are pretty accurate with the calculation of his data, as we know his exact system weight. The table below shows the calculated CdA values expressed in aeroPOINTs (CdA of 0.26 m2 equals 26 aeroPOINTS).


Michael Weiss Lionel Sanders Ben Hoffmann Jesse Thomas Per Bittner Jordan Rapp Joe Skipper Ronnie Schildknecht
Time 4:25:55 4:25:55 4:29:08 4:36:11 4:53:16 4:34:00 4:50:00 4:36:33
Power in W 304 306 253 257 257 272 254 274
aeroPOINTS 26.2 27 22.6 24 29 26 28 26.5


All calculations were made with the raw data available to us. The aeroPOINTs of Ben Hoffman and Per Bittner show a broad spread of 7. These two athletes are a pretty good example for the importance of aerodynamics since their system weight and power data are pretty similar. A decrease in aeroPOINTs by one point gives a time advantage of a little bit over three minutes on the 180 kilometer bike course of the Ironman Hawaii. If we take the difference of 7 aeroPOINTs, this multiplies up to the 24 minutes time difference.

Kona is due to the weather conditions always something very special to look at. The race regulations are not optimal for aerodynamic setups as disk wheels are prohibited. Therefore, the mentioned aeroPOINTs are not the optimum the athlete could reach.

However, they are a very good starting point for our Kona blog series that we are using to give you a basic understanding of our aeroCAST tool.