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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Machine-readable spec so AI agents can integrate this API.

/api/spokelength-api/openapi.json

/api/spokelength-api/llms.txt

Discovery: GET /api/index.json lists every API.

API health

healthy

Uptime: 100.00%; Server probes · 24h
Avg latency: 83 ms; Server probes · 24h
Subscribers: 4,173; active
Total calls: 3; last 7 days

Full status page → · 6 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

Other APIs with overlapping tags.

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

Grain Bin API

Grain-bin storage maths as an API, computed locally and deterministically — the bushel and weight numbers a farmer or elevator sizes storage by. The bushels endpoint measures a round bin: floor area × grain depth gives the cubic feet, and a cubic foot holds about 0.8036 bushels, so an 18-foot bin filled 20 feet level holds roughly 4,090 bushels — and grain heaped to a peak adds a cone of (1/3) × floor area × peak height, so a 4-foot peak adds about 270 more. The weight endpoint converts bushels to weight by the crop’s standard test weight — corn and sorghum at 56 pounds a bushel, wheat and soybeans 60, oats 32, barley 48 — so those 4,090 bushels of corn weigh 229,040 pounds, about 114.5 US tons or 104 tonnes; pass a measured test weight for light or heavy grain. Everything is computed locally and deterministically, so it is instant and private. Ideal for agriculture, grain-elevator, farm-management and ag-tech app developers, storage-capacity and inventory tools, and harvest software. Pure local computation — no key, no third-party service, instant. US units (feet, bushels, pounds). Live, nothing stored. 2 compute endpoints.

api.oanor.com/grainbin-api

ADA Ramp API

ADA wheelchair-ramp maths as an API, computed locally and deterministically — the run, landing and slope numbers a builder or accessibility planner sizes a ramp by. The rule the ADA fixes is 1 inch of rise per 12 of run, a maximum 8.33 % slope, so the ramp endpoint turns a rise into the ramp: run = rise × 12 (or × 16 / × 20 for a gentler grade if you have the room), plus the level landings the code requires — a 5-foot landing top and bottom and another between runs whenever the rise exceeds 30 inches — and the total length end to end, so a 24-inch rise needs a 24-foot run and 34 feet overall, while a 36-inch rise breaks into two runs with an intermediate landing for 51 feet. The fit endpoint answers the real-world question: does a ramp for this rise fit the run you have? It returns the minimum run an ADA 1:12 ramp needs, whether your space is enough, and the slope you would actually get if you forced it in — flagging when that exceeds 8.33 % and you need a switchback or a lower rise. Everything is computed locally and deterministically, so it is instant and private. Ideal for construction, accessibility, home-modification and contractor app developers, ramp-estimator and code-check tools, and building software. Pure local computation — no key, no third-party service, instant. Confirm against current ADA and local code. Live, nothing stored. 2 compute endpoints.

api.oanor.com/adaramp-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

API health

Pricing

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Related APIs

Bicycle Gear API

Cycling Performance API

Grain Bin API

ADA Ramp API

Frequently asked questions

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