Have bike design improvements resulted in faster times on the bike course at the Ironman World Championships in Kona?
When Jack Mott of Austin Tri Cyclist wrote a very provocative data crunch after the 2014 Ironman World Championships, he theorized that pro Ironman athletes have been getting progressively faster on the bike course in Kona, thanks to improvements in bike design. To test this theory, he compared the average bike split of the top 10 finishers in Kona every year since 1988. Then he ran another comparison of the fastest bike splits for each year. It's a compelling argument, but there could be a few other factors that influence the times from year to year.
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There's no such thing as a "fast bike." There are bikes that are built to move fast, but they only do that when people pedal them hard enough. There are bikes that make it easier to go fast, either by reducing aerodynamic or gravitational resistance, but that's the key thing to remember. A bike can get lighter or more aero, but how fast it goes is up to you.
That means there's an alternate theory to Mott's: Instead of bikes getting more aero, athletes are actually generating more power. We all know that today's triathlon bikes are undoubtedly better than those of 1988. Yet it also seems reasonable that the athletes of today are better as well. So really it must be some combination of man and machine. But what's the ratio of improvement?
Comparing the top 10 Kona finishers each year between 1988 and 2014, Mott found that average bike splits have dropped from 283.7 to 275.4 minutes in the last 26 years. There are two ways of viewing this. The easier way is to think of it in terms of overall time savings. Scott Molina finished the bike leg of the 1988 Ironman Championship in 4:36:50, or 277 minutes. Sebastian Kienle finished this year in 4:20:46, or 261 minutes. The difference between their times is 16 minutes, which is 5.8 percent of Molina's time. In this view, the question is whether Kienle's bike is 5.8 percent "better" than Molina's.