The books, papers and test data our calculators rely on, and what each one is used for.
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These sources supply the constants and structure for the cycling watts calculator and the tools that share its engine. Where a figure is an estimate, the page that uses it says so.
| Source | Used for |
|---|---|
| Jeukendrup, A. (ed.), High-Performance Cycling (2002), Human Kinetics | Riding-position CdA values (tops, hoods, drops, aerobars) |
| BicycleRollingResistance.com independent tire tests | Crr values by tire type on a paved surface |
| Ridefar drivetrain-efficiency testing | Chain and derailleur pulley losses |
| Cyclist magazine aero-wheel figures | Wheelset CdA reduction (treated as an estimate) |
| Analytic Cycling and similar bike-power calculators | The structure of the gravity, drag, rolling and drivetrain model |
The FTP, zone, W/kg, TSS and critical power calculators follow published definitions. The FTP test multipliers of 0.95, 0.90 and 0.75 are common field-test conventions rather than physiological constants, and the FTP calculator labels them that way.
| Source | Used for | Calculator |
|---|---|---|
| Allen, H. & Coggan, A. (2010), Training and Racing with a Power Meter (2nd ed.), VeloPress | Seven power zones, the W/kg power profile and the TSS and Intensity Factor definitions | Power zones calculator |
| Coggan, A.R. (2008, updated 2026), Creating Your Power Profile, TrainingPeaks blog. The printed men's and women's values were read from a republication of the book's table by Cyklopedia, used with VeloPress permission | The W/kg reference table, and the rule of assigning a result to the nearest printed ranking | W/kg calculator |
| Ferrari, M., as reported in the Wikipedia article VAM (bicycling), citing CyclingNews interviews (2003 to 2007) | The definition of VAM and the professional tiers of about 1,300 to 1,800 m/h. Amateur ranges on the VAM page are rules of thumb, not from a study | VAM calculator |
| Nehr, Z. (2026), Why This Tour de France Could Mark the Start of the 7w/kg Era, Velo; Walsh, A. (2026), The Science of Climbing at Tour de France Speeds, Roadman Cycling | Professional climbing W/kg of roughly 6 to 7. These are analyst estimates worked back from climb times, not published team data | Cycling watts calculator |
| Pérez-Piñero, S. et al. (2024), Effect of high-dose β-alanine supplementation on uphill cycling performance in World Tour cyclists: a randomised controlled trial, PLoS One 19(9): e0309404 (CC BY) | A measured reference point for professionals: 11 World Tour riders averaged about 5.7 to 6.1 W/kg on a roughly 10-minute, 5% climb in a training-camp test | Cycling watts calculator |
| Gallo, G. et al. (2023), Relationships between training dose and record power outputs in professional road cyclists, Biology of Sport 40(2): 485-495 (CC BY-SA) | Best 20-minute power of 46 World Tour riders, about 350 to 399 W depending on the period. Authors report watts only; the W/kg equivalent on the homepage is our own division by the group's mean body weight | Cycling watts calculator |
| Coggan, A.R., Normalized Power, Intensity Factor and Training Stress Score, TrainingPeaks | The published definition of NP, IF and TSS | TSS calculator |
| Monod, H. & Scherrer, J. (1965), The Work Capacity of a Synergic Muscular Group, Ergonomics 8(3), 329-338 | The two-parameter critical power and W′ model | Critical power calculator |
| Moritani, T. et al. (1981), Critical power as a measure of physical work capacity and anaerobic threshold, Ergonomics 24(5), 339-350 | Critical power as a fatigue threshold | Critical power calculator |
| Poole, D.C. et al. (2016), Critical power: an important fatigue threshold in exercise physiology, Medicine & Science in Sports & Exercise 48(11), 2320-2334 | The valid duration range for the critical power model | Critical power calculator |
Sources are recorded before a calculator is built, together with its assumptions and a hand-derived test value. The methodology page explains the testing, and the editorial policy describes how we respond when a source turns out to be wrong or out of date.
Spotted a missing or mis-cited source? Send it through the contact page and we will check it.
