Race Silicone Swim Cap
Reference models: Roka Hi-Vis Race Cap, FINIS Silicone Pro, Speedo Plain Silicone
CWPM vs Swim 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 swim sets the empirical κ bump; Tbaseline is the leg duration at your profile.
Time saved vs Swim 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 swim sets κ; Tbaseline is your 140.6 Full swim 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 — swim alternatives
Every swim 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
A snug silicone cap smooths flow over the skull — the leading edge of the swim — and reduces drag at the head. Cheap, effective, and the only piece of equipment where doubling up (two caps) is actually a known marginal-gains hack used by elites.
Hydrodynamic drag — a fractional speed gain scaled by $(v/1.05)^{0.4}$ for faster swimmers.
Source basis for the savings estimate
1 referenceThe Speed gain = 0.7% 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.
- Which is the swim cap of choice? An analysis of the hydrodynamic drag of four different swim caps.Journal of Sports Sciences, 32(8):1131–1137.Cap-to-cap drag differential — small but measurable.doi.org/10.1080/02640414.2014.886209
How the savings estimate was built
Speed gain 0.7%Flume / CFD studies → fractional speed gain → minutes per hour.
- Reference flume measurements or CFD studies of equivalent suit/cap/goggle gear.
- Express the result as a fractional speed gain (Δtime%); ΔM/h = 60·Δtime%.
- Scale by (v/1.05)^0.4 in-model so faster swimmers see proportionally more benefit.
This is a calibrated model number, not a measurement of your equipment.
The value reflects published delta-ranges for the Surface Friction category
with a swim 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.