Swiss Side Tech Insights into the Ironman World Championships in St. George
Swiss Side CEO Jean-Paul Ballard is in St.George making aerodynamics and R&D testing for both our internal development but also to support our athletes competing at this Ironman World Championship race.
A lot of work has been done already ahead of St.George simulating the race course and the investigating key performance factors such as wind, weight, and aero drag, so as to find the best setups for our athletes. Furthermore, the wind plays a big role in both aero setup and the race strategy here in St. George, so this has been a focal point of our testing.
Testing is being done by riding the course with our CdA-meter which not only measures aerodynamic drag, but importantly also the wind strength and angle seen by the rider on the road. Each day, Jean-Paul and other athletes have been riding the course, and the engineers back in Switzerland have been further analysing the data, also comparing with local wind forecasts.
Here are some key insights into what we have learnt so far:
• St.George lies at around 1000m altitude so the lower air density leads to lower aero drag and higher speeds compared to Kona at sea level. However the course is quite hilly with 2265m climbing compared to 1386m in Kona. We calculate that the bike course time in St.George will be around 10 minutes slower than Kona.
• Aero importance remains dominant in St.George but slightly reduced in importance compared to Kona. A 5% aero drag saving equates to around 3 min 20 sec time saving. (This is 40sec less than in Kona due to the increased climbing in St.George). So around 85% aero drag effect here in St.George compared to Kona.
• Weight importance increases in St.George due to the climbing. This is rider dependent but to give an example for one lighter athlete: In St.George 1kg additional weight equates to around a 66 seconds time penalty. In Kona this would be 31 seconds. So around 200% the weight effect here in St.George compared to Kona.
• In summary of the aero vs weight effects: 1.6% aero drag = 1kg weight in St. George.
• The wind has been very variable and on some days extremely strong. It’s as strong if not stronger than in Kona but even more gusty.
• The best wheel setups for the pros will be HADRON2 Ultimate 800 front wheel with the DISC rear, if the wind permits. For some athletes, they may switch to a 625 front wheel if the wind is too strong.
• For our age group athletes, we recommend 800/800 setup for the strong and
experienced riders, or if wind is strong, a 625/800 setup which provides a 25%
reduction in front wheel sensitivity to the wind at a small aero penalty (1W at 45km/h.–Depending on the wind, this can increase).
• The road is quite rough so slightly lower tyre pressures are beneficial. Depending on rider weight, around 1 bar less than on smooth roads based on 25mm tyres. This will also help with regards to punctures. There is quite a lot of debris on the road here, so we also don’t recommend super lightweight tyres without a puncture protection layer.
• Speed on the descents will play a role for the pro field so some high gearing is
important to maximise top speed on the descents. Expects some attacks on the
• The most favourable wind direction for aero performance in St.George, giving the highest time savings thanks to sailing effect is from the North. The least favourable wind direction is from the South. The Swiss Side pro-athletes competing on Saturday are:
• Jan Van Berkel (Switzerland)
• Andi Dreitz (Germany)
• Denis Chevrot (France)
• Lisa Norden (Sweden)
• Daniela Ryf (DT-Swiss Aerodynamics by Swiss Side athlete – Switzerland)
Unfortunately due to injury or illness the following Swiss Side athletes won’t be on the starting line in St.George: Patrick Lange, Rasmus Svenningsson, Laura Philipp, Justine Mathieux.
The run course is also very hilly and challenging. Coupled with the heat in the afternoon, those who are a little more conservative and paced on the bike course, could benefit on the run. Equally those who push to hard on the bike might pay for it on the run.
In any case, it is a very different World Championship race than Kona and will test all athletes in a different way.
We are of course crossing our fingers that all our Swiss Side athletes, pros and age-groupers alike, can deliver their best possible performance on the day, and leave it out on the course. Whether that is enough for a podium will be played out on Saturday!