Tier-2 Carbon-Plate Trainer (Ironman-Ready)
Reference models: Saucony Endorphin Pro 4, Hoka Rocket X 2, Nike Alphafly 2
CWPM vs Run pace
Cost per minute saved across the full slider range, all other parameters held at your current profile.
FORMULA CWPM = cost ÷ Δt, where Δt = (min/h at your speed) × κ(slider) × Tbaseline(slider).
Curve run sets the empirical κ bump; Tbaseline is the leg duration at your profile.
Time saved vs Run pace
Minutes shaved at the 140.6 Full format as your slider value varies.
FORMULA Δt = (min/h at your speed) × κ(slider) × Tbaseline(slider).
Curve run sets κ; Tbaseline is your 140.6 Full run leg duration.
Time saved across race formats
Minutes shaved if you raced each distance at your current profile.
FORMULA For each format f: Δtf = (min/h at your speed) × κ(profile) × Tbaseline(f). Only the leg distance — and therefore Tbaseline — varies between bars; κ is held constant from your profile.
Cost vs time saved — run alternatives
Every run upgrade in the catalog plotted at your current profile. The line is the Pareto frontier: anything above it is dominated by a cheaper item that saves the same or more time.
HOW TO READ Each dot is one upgrade. Its horizontal position is the time it would save you at your current profile — the same Δt computed in the charts above. Its vertical position is the upgrade's cost. The green dashed line is the Pareto frontier: items where no cheaper alternative matches or beats them on time saved. Anything floating above the line is dominated — somewhere down-and-to-the-right sits a frontier item that delivers the same or more minutes for less money, so it's the better buy.
Why it works
Mid-tier carbon-plate super-shoe with a thicker, more durable foam stack. Marginally less responsive than top-tier racers but engineered for Ironman-length wear-down and consistent energy return through the marathon split.
Running economy — a fractional speed gain scaled by $(v/3.33)^{0.25}$ for faster runners.
Source basis for the savings estimate
2 referencesThe Speed gain = 3.2% primitive is a calibrated
midpoint drawn from the literature below. Peer-reviewed studies are weighted most heavily;
independent / industry labs fill gaps where peer review is sparse for this gear category.
- A comparison of the energetic cost of running in maximalist, traditional and minimalist running shoes.Sports Medicine, 48(4):1009–1019.The "Vaporfly 4%" study — first lab evidence of ~4% running economy gain from carbon-plate, high-stack foam shoes.doi.org/10.1007/s40279-017-0811-2
- A randomized crossover study investigating the running economy of highly-trained male and female distance runners in marathon racing shoes versus track spikes.Sports Medicine, 49(2):331–342.Sex-balanced crossover — useful for tempering the headline 4% figure across athlete profiles.doi.org/10.1007/s40279-018-1012-3
How the savings estimate was built
Speed gain 3.2%Metabolic / VO₂ economy studies → fractional speed gain → minutes per hour.
- Use published running-economy deltas for the gear category, expressed as a fractional speed gain (Δtime%).
- ΔM/h = 60·Δtime%, scaled by (v/3.33)^0.25 — faster runners realize slightly more of the gain.
- Conservative midpoint chosen when peer-reviewed and brand-funded studies disagree.
This is a calibrated model number, not a measurement of your equipment.
The value reflects published delta-ranges for the Footwear category
with a run response, biased toward independent rather than manufacturer data.
The slider sweep above shows how watts-saved at your speed and the curve κ reshape it across athlete profiles.