#cycling

Bicycle wheel-building maths as an API, computed locally and deterministically — the spoke-length and tension numbers a wheelbuilder laces a wheel by. The spoke endpoint runs the classic spoke-length formula from the hub and rim geometry: L = √(R² + r² + f² − 2·R·r·cos θ) − hole ÷ 2, where R is half the effective rim diameter (ERD), r is half the hub flange diameter, f is the centre-to-flange offset and θ = crosses × 720° ÷ spokes — so a 602 mm ERD rim on a 45 mm flange at 35 mm offset, 32 spokes laced 3-cross (a 67.5° crossing angle), needs a 293.9 mm spoke. It handles radial (0-cross) builds and computes the drive and non-drive sides separately from their own offsets, since a dished wheel’s two sides differ. The bracing endpoint gives each side’s bracing angle = atan(offset ÷ (ERD/2)) — the lever that resists side loads — and the resulting tension ratio, because the side with the smaller offset must carry higher tension, which is why a rear wheel’s non-drive spokes (often only about half the drive-side tension) go slack first. Everything is computed locally and deterministically, so it is instant and private. Ideal for bike-shop, wheelbuilding, cycling and bike-fit app developers, spoke-calculator and build-sheet tools, and component-database software. Pure local computation — no key, no third-party service, instant. Millimetres. Live, nothing stored. 2 compute endpoints. For gear inches or gearing use a bicycle-gear API.

api.oanor.com/spokelength-api

Bicycle gearing maths as an API, computed locally and deterministically. The gear endpoint takes a chainring and cog tooth count and a wheel size and returns every common gearing metric: the gear ratio, gear inches (the classic measure — ratio times wheel diameter in inches), the gain ratio (Sheldon Brown's crank-length-aware measure), the development or rollout (metres travelled per crank revolution), and the road speed at a chosen cadence in km/h and mph. The speed endpoint converts between a gear-and-cadence and road speed in either direction — the speed at a cadence, or the cadence needed for a target speed. The table endpoint builds a gear chart: give one or more chainrings and a cassette of cogs and it returns a matrix of gear inches, development, gain ratio or ratio for every combination — ideal for visualising a drivetrain. Wheel size can be a preset (700x25c, 26-inch, 29er and more) or an exact rolling circumference in millimetres, and crank length is configurable for the gain ratio. Everything is computed locally and deterministically, so it is instant and private. Ideal for cycling apps and bike-fit tools, drivetrain and gear-ratio planners, and bike-shop and component sites. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is bicycle gearing; for cycling power, FTP and training zones use a cycling API.

api.oanor.com/bikegear-api

Matemáticas de rendimiento ciclista como API. El endpoint de potencia estima la potencia en vatios necesaria para pedalear a una velocidad dada en una pendiente determinada, a partir de un modelo físico — resistencia a la rodadura, gravedad en la subida y arrastre aerodinámico — con valores predeterminados sensatos que puedes anular (coeficiente de resistencia a la rodadura, área de arrastre CdA, densidad del aire, eficiencia de la transmisión y viento en contra), y desglosa la potencia en sus componentes de rodadura, gravedad y aerodinámica, además de vatios por kilogramo. El endpoint ftp-zones convierte una Potencia Funcional Umbral en las siete zonas de entrenamiento de Coggan, desde recuperación activa hasta potencia neuromuscular, como rangos de vatios. El endpoint vam calcula el VAM — metros de ascenso vertical por hora, la métrica de velocidad de escalada — ya sea a partir de la elevación ganada y el tiempo, o de la velocidad y la pendiente. Todo se calcula local y determinísticamente, por lo que es instantáneo y privado. Ideal para aplicaciones de ciclismo y entrenamiento, ordenadores de bicicleta y herramientas de medidores de potencia, entrenamiento, y análisis de rutas y subidas. Cálculo local puro — sin clave, sin servicio de terceros, instantáneo. En vivo, nada almacenado. 4 endpoints. Esto son matemáticas de ciclismo; para ritmo de carrera usa una API de ritmo y para zonas de frecuencia cardíaca de entrenamiento usa una API de frecuencia cardíaca.

api.oanor.com/cycling-api