10 % more power or 10 % more aero?

More power or better aerodynamic? This is my thought about this existential question.

Would you rather increase your FTP with 10 % or reduce your aerodynamic drag with 10 %? If you gave this option to triathletes I am certain that most would opt for the increased FTP. But it is the best option?

This could all be solved by relatively simple math. Then the answer would be overly theoretical. Instead, I choose to use super complicated math with BestBikeSplit, one of my sponsors, calculating the differences with the rider «Average Joe» in two different courses. One is the flat Ironman Texas and the other is the hilly Norseman bike course.

Average Joe is 76 kg + 10 kg bike/equipment with an FTP of 265 watts in Ironman Texas and slightly heavier with 80 kg and same FTP in Norseman.

11 minutes and 16 seconds is the time saved of increasing the watt with 10 %.

10 minutes and 2 seconds is the time saved by decreasing the drag with 10 %. 

A whopping 22 minutes and 58 seconds can be made in Norseman by increasing the watt with 10 %.

7 minutes and 54 seconds is the savings with 10 % less drag in a hilly course.

From this, we could conclude that 10 % increase in FTP(or average power in a race) is better than 10 % decrease in drag. Slightly faster on flat courses and much faster in hilly courses.

That would be true if we did not take into account that in order to increase the average power with 10 %, you also have to use at least 10 % more energy. In the excel sheet below I have calculated how long time you have before running out of energy at 200 watts compared to 180 watts output. In my calculations, the 200 watts will give nearly 200 kCal deficit each hour, and last just over 10 hours. The 180 watts in the other case will only go with 129 calories deficit each hour and last 15,5 hours, 50 % longer.

The calculations are overly simple (maybe the amazing number crushers in BestBikeSplit should make a nutrition calculator as well), and in real life, it would be different factors playing a part. Still, if you are going to push more watt, you are going to run out of energy faster. Available energy is a limiter for everyone doing an Ironman at one point unless you are the unlikely case of having a very good fat utilization and ride with low watts.

For this reason, and the fact that most triathlon races are flat, I believe 10 % less aerodynamic drag is better than 10 % increase in power.

The anwser to this question question is interesting, yet completely useless. There is no reason to choose one before the other. Thru proper training, eating and recovery you should try to become as fit as you can, aka increasing power. And thru using a small amount of effort and not too much money improvement in aerodynamic drag of 10 % or better should be achievable. Why choose when you can take both?

In my project #FasterThanSuperman, where I try to become the most aerodynamic triathlete in the world, I have learned a lot. Learned what truly give the big aerodynamics gains and what yields minor improvements. In future blog posts, I will share my thoughts about this topic. If you want to be sure to see it push on the sign up botton below and get an email each time I publish a post.

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I am a 33 year old PRO triatlete. My goal is to swim, bike and run as fast as possible, and enjoy the journey. All my adventures and triathlon related stuff is well documented on this blog.

Én kommentar til “10 % more power or 10 % more aero?

  1. Hej Allan,

    Sjov analyse… Jeg tror bare ikke at du finder en atlet, der vil vælge. Vi vil vel alle gerne både have mere power OG mindre drag… Omkring selve analysen, så tænker jeg at mere power får endnu mere betydning på begge strækninger hvis man kunne indregne styrke-effekten i løbet også. +10% FTP på cykel må sikkert hjælpe på vej opad i løbet.

    Go Man!



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