Oversized Pulley Wheels (OSPW)
Reference models: CeramicSpeed OSPW, Kogel Kolossos
CWPM vs Sustained bike power
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 static sets the empirical κ bump; Tbaseline is the leg duration at your profile.
Time saved vs Sustained bike power
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 static sets κ; Tbaseline is your 140.6 Full bike 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 — bike alternatives
Every bike 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
Larger pulley diameter reduces chain articulation losses at the derailleur cage. The dividend is real but small — check the CPMS carefully; this is one of the lowest-yield upgrades in the catalog despite the price tag.
Constant drivetrain saving — fixed watts regardless of speed, so time benefit falls as $P^{-1}$: weaker riders gain the most.
Source basis for the savings estimate
1 referenceThe Watts saved = 2 W 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.
- Drivetrain efficiency measurements: chain lubricants, oversized pulleys and bottom-bracket bearings.Watt-loss measurements at race power on a calibrated dynamometer; widely cited in cycling efficiency analyses.ceramicspeed.com/en-eu/pages/drivetrain-efficiency-test-old-vs-new
How the savings estimate was built
Watts saved 2 WChain-efficiency benchmarks → constant watts saved.
- Source steady-state drivetrain efficiency deltas from third-party labs.
- The saving is a constant number of watts, independent of speed.
- Via ΔM/h = 20·ΔP/P the time benefit falls as P^(−1) — weaker riders gain the most.
This is a calibrated model number, not a measurement of your equipment.
The value reflects published delta-ranges for the Drivetrain category
with a static 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.