The IRONMAN World Championship 2017 is history and most of us triathletes are looking forward to the off-season. It’s a good time to review the past triathlon season and to learn from the gained experience. It is also a good time to work on your bike position for the next year. Your muscular apparatus needs time to get used to new seating positions and physical changes that come along with it.


Aerodynamics is one of the great “Lessons Learned 2017”. For a last time, we want to take a look at the Ironman pros and their aerodynamics. Already in the run-up to the World Championship, we had carried out calculations of the pros with our aeroCAST tool and, in some cases, also blogged about them.


First, let’s look at the two world champions Patrick Lange and Daniela Ryf: For Patrick we had calculated a bike split between 4:29 hrs. and 4:33 hrs., he rode 4:28:55 hrs. For Daniela our forecast stated a time between 4:46 hrs. – 4:50 hrs. After her incredible 40km bike finishing sprint, she came in at 4:53:10 hrs.


We have often mentioned it: Aerodynamics is one of the biggest influencers on the time wise performance. This could be seen on Hawaii, too. Despite the slightly more favorable weather, almost all professionals were faster compared to the previous year. Considering to what extent improvements in performance are possible within one year, or considering the respective watts of both years, it can only be concluded that many athletes have made great aerodynamic improvements on their position or equipment.


In one of our Facebook blogs, we expected a bike split between 4:14 hrs. – 4:20 hrs. for Lionel Sanders. Our forecast relied on the distance he would have to the first large swimming group, as Lionel would align his racing strategy accordingly. With 6 minutes, the time difference was at the higher end of expectations. Lionel was one of the three triathletes, who broke the previous bike split record of Norman Stadler. Lionel’s bike split of 4:13:59 hrs. fits quite well into our forecast by means of the aeroCAST. Looking at Trainingpeaks we know Lionel’s performance data and have retroactively calculated a CdA of 0.235 m2 (aeroSCORE: 23.5 aeroPOINTS) for him.


Below a few more calculations using the aeroCAST based on the assumed power performance and analysis of the position:

Jan Frodeno Sebastian Kienle Ben Hoffman Jesse Thomas Terrenzo Bozzone Boris Stein
aeroCAST 4:18 – 4:24 4:14 – 4:20 4:20 – 4:24 4:30 – 4:34 4:24 – 4:28 4:18 – 4:25
Bike split 4:21:00 4:14:57 4:21:17 4:33:08 4:26:20 4:23:59


In the next days, we will explain the aeroCAST in detail to you, also in combination with the aeroTEST, so you can experience the possibilities and advantages they give you.