Originally Posted by
burnthesheep
Distance.
Issue is that 25w faster over two 5k runs per the runner power pace calculator is more time saved than 25w more over the 30k bike leg in a duathlon.
So:
300w run and 325w bike is slower in a 5k/30k/5k than a 325w run and 300w bike.
I made a little Excel sheet to prove it out.
Basically if you can run 5min miles you can really suck at the bike and win but the bike cannot use mammoth watts to makup the same time. Because the faster a cyclist goes the more power it takes and the less time they gain.
Pace power calc here: Couzens
https://alancouzens.com/blog/Run_Power.html
Run your model on a very hilly and technical course, and the results skew even more.
Lots of cyclists ride a 100 miles on both a Saturday and a Sunday. How many runners have ever run a Marathon two days in a row? OP's question does not have an easy answer and in my view, there isn't one if considering difficulty (stress on the body and mind). Cycling is way easier.