Comparing Josh Amberger and Lionel Sanders Bike Splits at Ironman Hawaii 2018.
I recently received an interesting question from one of our athletes that is worth sharing:
Lionel Sanders was 2min faster than Josh Amberger (at the Ironman World Champs), but held 62watts more power over the 4 hours and 20 minutes ride. Why such a big discrepancy in power? Google has their weights listed as Lionel being 11 lbs more. Would 11 lbs require 60+ more watts? Damn.
297 Avg Power
26.2 Avg MPH
- First off, I believe Josh on his Felt IA is in a more naturally aerodynamic position than Lionel. It's worth googling pics of Josh and Lionel and seeing the difference. This isn't to say that Lionel has a "bad" bike fit. I fully expect it is near the best position his body can have on a bike. It's more an acknowledgment that some people can fold themselves into a more natural aerodynamic position than others.
- The Felt IA is consistently one of the most aerodynamic bikes money can buy in *all wind conditions* (many bikes are only tested aerodynamically in a headwind, which is not what Kona typically delivers). Maybe that is worth 5-10 watts.
- Josh is listed as 5'7'' tall. He is also not a particularly broad-shouldered athlete. Lionel is 5'10'' tall, with more muscle up top. Surface area has a lot to do with aerodynamics, and in particular you want to keep the leading edge of "your personal vessel" as narrow and small as possible. Broad shoulders, muscle, etc all creates more drag. Maybe this is worth another 10-15 watts.
- Like you said, Josh is 10-15lbs lighter than Lionel, which could be worth a few more watts.
- But most importantly, Josh was in the lead bike group, and Lionel had to mostly bike alone the entire day. From the data I've been able to collect over the years, being in the lead group is worth about 10% power savings. For example, local stud Guy Crawford is a few inches taller than Lionel, and weighs only a few pounds more. At the 70.3 World Champs last year, Lionel and Guy had almost the exact same bike split, but Guy was in the lead group, and Lionel rode solo a few minutes back. Guy held ~320-330 watts for the 56miles, and Lionel posted his power in his typical 70.3 power range of 350-360 for the same race. About 10% difference between the two athletes. My conclusion is that missing the main swim group probably cost Lionel 20-30 watts of "legal drafting" benefit at this event.