API · /spokelength-api

Spoke Length & Wheel API

healthy 4,173 Subscribers

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.

#cycling #wheelbuilding #spoke #bike #bike-shop #developer-tools

api.oanor.com/spokelength-api

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/api/spokelength-api/openapi.json

/api/spokelength-api/llms.txt

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Spoke Length & Wheel API — live data on the oanor API marketplace

API health

healthy

Uptime: 100.00%; Server probes · 24h
Avg latency: 79 ms; Server probes · 24h
Subscribers: 4,173; active
Total calls: 60; last 7 days

Full status page → · 12 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

6,900 calls / month
2 requests / second
Hard cap (429 above quota, no overage)
6,900 calls/month
2 req/sec
Spoke length + bracing + tension ratio
No credit card

Starter

€4.35 /month

54,500 calls / month
6 requests / second
Hard cap (429 above quota, no overage)
54,500 calls/month
6 req/sec
Drive/non-drive sides, radial, any cross
Email support

Pro

€12.00 /month

226,000 calls / month
15 requests / second
Hard cap (429 above quota, no overage)
226,000 calls/month
15 req/sec
Spoke-calculator & build-sheet pipelines
Priority support

Mega

€38.00 /month

1,330,000 calls / month
40 requests / second
Hard cap (429 above quota, no overage)
1,330,000 calls/month
40 req/sec
Platform scale
Dedicated SLA

Built by

PremiumApi

Related APIs

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Bicycle Gear 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

Cycling Performance API

Cycling performance maths as an API. The power endpoint estimates the power in watts needed to ride at a given speed on a given gradient, from a physical model — rolling resistance, gravity on the climb, and aerodynamic drag — with sensible defaults you can override (rolling-resistance coefficient, drag area CdA, air density, drivetrain efficiency and headwind), and breaks the power down into its rolling, gravity and aero components plus watts-per-kilogram. The ftp-zones endpoint turns a Functional Threshold Power into the seven Coggan training zones, from active recovery to neuromuscular power, as watt ranges. The vam endpoint computes VAM — vertical ascent metres per hour, the climbing-speed metric — either from elevation gained and time, or from speed and gradient. Everything is computed locally and deterministically, so it is instant and private. Ideal for cycling and training apps, bike computers and power-meter tools, coaching, and route and climb analysis. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 4 endpoints. This is cycling maths; for running pace use a pace API and for heart-rate training zones use a heart-rate API.

api.oanor.com/cycling-api

Programming Languages API

The language definitions GitHub uses to recognise code (the open-source Linguist data) as an API — a clean reference for syntax highlighting, file-type detection, repository dashboards and developer tooling. For each of 800+ languages the API returns its type (programming, markup, data or prose), its brand colour (the hex GitHub paints it), the file extensions associated with it, common aliases, the GitHub language id and the editor (ace) mode. Look a language up by name or alias (golang resolves to Go), reverse-look-up which language(s) own a file extension (.py → Python; .h → C, C++, Objective-C), list the languages of a type, search, or list them all. Distinct from languages-api (ISO 639 human languages) — this is the programming-language reference. Served from memory — always fast.

api.oanor.com/proglang-api

MIME Types API

The canonical MIME / media-type database (the jshttp mime-db used by Express and most of the Node ecosystem: IANA + Apache + nginx), served from memory — no key. Resolve a media type to its file extensions, charset and compressibility; reverse-lookup the media type(s) for a file extension (e.g. png → image/png); and search or list types by source. 2,600+ media types, 1,000+ with file extensions. Lean, predictable JSON. Ideal for upload validation, Content-Type resolution, file-type detection, download handlers and developer tooling.

api.oanor.com/mimetypes-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Spoke Length & Wheel API?

Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Spoke Length & Wheel API with the x-oanor-key header. No credit card needed for the free tier.

What's the rate limit for Spoke Length & Wheel API?

Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.

How much does Spoke Length & Wheel API cost?

Spoke Length & Wheel API has a free tier with 100 calls / month. Paid plans start at €4.35 / month with higher quotas and faster rate limits.

Can I cancel my subscription anytime?

Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.

Is Spoke Length & Wheel API GDPR-compliant?

All requests to Spoke Length & Wheel API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Wheel 2

Meta 1

Pick an endpoint from the list on the left to see its details and try it.

GET /v1/bracing

Bracing angle + tension ratio

Playground

Parameters

Custom headers

Language: Client:

GET /v1/spoke

Spoke length

Playground

Parameters

Custom headers

Language: Client:

GET /v1/meta

Spec

Playground

Custom headers

Language: Client:

Code snippets

curl https://api.oanor.com/spokelength-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."

const res = await fetch("https://api.oanor.com/spokelength-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();

$ch = curl_init("https://api.oanor.com/spokelength-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);

import requests
r = requests.get(
    "https://api.oanor.com/spokelength-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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Spoke Length & Wheel API

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Pricing

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Related APIs

Bicycle Gear API

Cycling Performance API

Programming Languages API

MIME Types API

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