API · /gearratio-api

Gear Ratio API

healthy 3,511 Subscribers

Gear-train ratio, speed and torque maths as an API, computed locally and deterministically. The ratio endpoint computes the gear ratio of a single pair from the driver and driven tooth counts (or pitch diameters), ratio = N_driven/N_driver, classifies it as a reduction (more torque, less speed) or an overdrive, and — given an input speed and torque — returns the output speed (input/ratio) and the output torque (input·ratio·efficiency). The train endpoint computes a compound gear train: the overall ratio is the product of the individual stage ratios, and it returns each stage ratio, the output speed and torque, noting that idler gears change only the direction of rotation, not the ratio. The solve endpoint finds the missing one of the input speed, the output speed and the ratio from the other two — for example, the ratio needed to drop a 1500 rpm motor to a 500 rpm output. Everything is computed locally and deterministically, so it is instant and private. Ideal for drivetrain, robotics and machine-design tools, gearbox and transmission selection, bicycle and vehicle gearing, and mechanical-engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is gear-train ratio and torque; for spur-gear tooth geometry use a spur-gear API.

#gear-ratio #gearbox #drivetrain #transmission #mechanical-engineering #developer-tools

api.oanor.com/gearratio-api

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/api/gearratio-api/openapi.json

/api/gearratio-api/llms.txt

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

Gear Ratio API — live data on the oanor API marketplace

API health

healthy

Uptime: 100.00%; Server probes · 24h
Avg latency: 75 ms; Server probes · 24h
Subscribers: 3,511; active
Total calls: 76; last 7 days

Full status page → · 12 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

3,000 calls / month
2 requests / second
Hard cap (429 above quota, no overage)
Single-pair gear ratio endpoint
Deterministic local compute, no upstream
JSON ratio + reduction output

Starter

€8.00 /month

40,000 calls / month
5 requests / second
Hard cap (429 above quota, no overage)
Ratio, output speed and torque maths
Multi-stage gear-train chaining
Driver/driven tooth-count inputs
Email support

Pro

€22.00 /month

250,000 calls / month
20 requests / second
Hard cap (429 above quota, no overage)
Full drivetrain & gearbox modelling
Compound and planetary gear stages
Batch ratio computation
Priority support

Mega

€69.00 /month

1,500,000 calls / month
60 requests / second
Hard cap (429 above quota, no overage)
High-volume drivetrain simulation throughput
All gear-train, speed & torque endpoints
Bulk batch + highest rate limit
SLA-backed dedicated support

Built by

PremiumApi

Related APIs

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Tire & Drivetrain API

Tyre, wheel and drivetrain maths as an API. The tire endpoint parses a metric tyre size such as 205/55R16 into all its real dimensions — section width, aspect ratio, sidewall height, rim and overall diameter in millimetres and inches, rolling circumference, and revolutions per kilometre and per mile. The compare endpoint takes an original and a replacement tyre size and works out the change in overall diameter and the resulting speedometer and odometer error — so you know how much faster you are really going than the dial shows after a tyre change. The gear endpoint computes a gear ratio from ring and pinion tooth counts, or the road speed from engine RPM, total gear ratio and tyre size. Everything is computed locally and deterministically, so it is instant and private. Ideal for automotive and motorsport apps, tyre shops and fitment tools, modding and restomod planning, and vehicle configurators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is tyre and drivetrain maths; for vehicle specifications by VIN use a vehicle-database API.

api.oanor.com/tirecalc-api

Worm Gear API

Worm-gear engineering maths as an API, computed locally and deterministically — the ratio, lead-angle and efficiency numbers a machine designer or millwright sizes a worm drive with. The ratio endpoint gives the reduction = wheel teeth ÷ worm starts, so a single-start worm on a 40-tooth wheel is a big 40:1 reduction in one compact stage — the high ratio in a small package is the whole appeal of a worm drive. The geometry endpoint gives the lead (= starts × axial pitch, with axial pitch = π × module) and the lead angle = atan(lead ÷ (π × worm pitch diameter)), and tests for self-locking: a small lead angle (roughly under 5–6° for typical steel-on-bronze) means the wheel cannot back-drive the worm — invaluable for hoists and holding loads, at the cost of efficiency. The efficiency endpoint gives the mesh efficiency when the worm drives = tan(lead angle) ÷ tan(lead angle + friction angle), which is low for the small lead angles that give big ratios — often 50–70 %, which is why worm gears run warm and need good lubrication — while high-lead multi-start worms reach 90 %+; when the lead angle drops to the friction angle the drive becomes self-locking. Everything is computed locally and deterministically, so it is instant and private. Ideal for mechanical-design and gearbox tools, machine-building and CAD utilities, and engineering calculators. Pure local computation — no key, no third-party service, instant. Confirm self-locking dynamically — vibration can unlock a marginal pair. 3 compute endpoints. For spur gears use a spur-gear API; for a general ratio a gear-ratio API.

api.oanor.com/wormgear-api

Roller Chain Drive API

Roller-chain drive maths as an API, computed locally and deterministically — the chain-length, sprocket and speed numbers a machine designer or millwright lays out a drive with. The chain-length endpoint gives the chain in pitches from the two sprocket tooth counts, the chain pitch and the centre distance: L = 2·C + (N1+N2)/2 + ((N2−N1)/2π)² ÷ C (C in pitches), rounded UP to an even number so the chain closes without an offset link — a 17- and 34-tooth pair at 15-inch centres on #40 (half-inch) chain comes to 86 pitches, 43 inches. The sprocket endpoint gives the pitch diameter, pitch ÷ sin(180°/teeth), and the outside diameter — a 17-tooth #40 sprocket has a 2.72-inch pitch circle. The speed endpoint gives the chain's linear speed, pitch × teeth × rpm ÷ 12, so a 17-tooth #40 sprocket at 100 rpm runs the chain at about 71 ft/min. Everything is computed locally and deterministically, so it is instant and private. Ideal for machine-design and drivetrain apps, conveyor and equipment-build tools, maker and CAD calculators, and engineering aids. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. For gear ratios use a gear-ratio API; for belts use a pulley API.

api.oanor.com/chaindrive-api

Clutch & Brake Torque API

Friction clutch and disc-brake torque as an API, computed locally and deterministically. The clutch endpoint computes the torque a plate (disc) clutch can transmit from the friction coefficient, the axial clamping force and the friction-face inner and outer radii, by both standard theories — uniform-wear, T = n·μ·F·(Ro+Ri)/2, and uniform-pressure, T = ⅔·n·μ·F·(Ro³−Ri³)/(Ro²−Ri²) — for any number of friction surfaces (a multi-plate clutch multiplies the torque), plus the maximum power at a given speed. The cone endpoint does the same for a cone clutch, T = n·μ·F·Rm/sin α, where the wedge angle amplifies the normal force by 1/sin α. The brake endpoint gives the braking torque of a disc brake, T = n·μ·F·R_eff, the power dissipated at a speed and — given a rotating inertia and its speed — the angular deceleration, the time and number of revolutions to stop, and the kinetic energy turned into heat. Everything is computed locally and deterministically, so it is instant and private. Ideal for drivetrain, automotive and machine-design tools, clutch, brake and winch engineering, and mechanical-engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is rotating-friction clutch and brake torque; for shaft torsion stress use a torsion API and for rope/belt capstan friction use a capstan API.

api.oanor.com/clutch-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Gear Ratio API?

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

What's the rate limit for Gear Ratio 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 Gear Ratio API cost?

Gear Ratio API has a free tier with 100 calls / month. Paid plans start at €8.00 / 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 Gear Ratio API GDPR-compliant?

All requests to Gear Ratio 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.

Gear 3

Meta 1

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

GET /v1/ratio

Single-pair gear ratio

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Parameters

Custom headers

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GET /v1/solve

Solve speed / ratio

Playground

Parameters

Custom headers

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GET /v1/train

Compound train ratio

Playground

Parameters

Custom headers

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GET /v1/meta

Spec

Playground

Custom headers

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Code snippets

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

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

$ch = curl_init("https://api.oanor.com/gearratio-api/SOME_PATH");
curl_setopt($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/gearratio-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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Gear Ratio API

API health

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Related APIs

Tire & Drivetrain API

Worm Gear API

Roller Chain Drive API

Clutch & Brake Torque API

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