No. 01 — The calculator
Which shoe is
worth your money?
Four questions. You get a costed recommendation: what it saves you over your race, what your finish time becomes, and what each of those seconds costs.
What this actually works out
Everyone quotes “4% faster”. That figure came from a laboratory study of fast runners, and it describes running economy — how much oxygen you use — not the time on the clock. Three things sit between it and your finish.
- 01
Economy is not time
A 4% economy gain is worth roughly 2.6% in speed, because drag and the metabolic cost of running do not scale linearly. Skipping that step overstates the benefit by more than half.
- 02
The benefit shrinks if you are slower
The plate and foam need force to give energy back. Nearly all the published testing was done at 14–18 km/h, so every estimate here is scaled down towards your actual pace.
- 03
You already own something
A gain has to be a gain over something. Naming what you race in now — a trainer, a plated tempo shoe, or the exact model — subtracts what you have already banked.
Then there is the money. These shoes stop returning energy somewhere between 120km and 300km — long before they fall apart — so the price that matters is the price per race, and the price per second. The full method is published, assumptions included.