Belt length from diameters & centres
API · /beltdrive-api
Belt Drive API
healthy
4,956 Subscribers
Belt-drive and pulley maths as an API, computed locally and deterministically. The belt endpoint computes the length of an open V-belt or flat belt from the two pulley diameters and the centre distance with L = 2C + (π/2)(D1+D2) + (D1−D2)²/(4C), and returns the belt length plus the wrap (contact) angle on each pulley; pass a driver rpm and it also gives the belt surface speed. The ratio endpoint computes the speed ratio of a pulley pair (driven ÷ driver diameter, since N1·D1 = N2·D2): give a driver or driven rpm and it returns the other, the torque ratio and the belt speed. The centers endpoint reverses the length equation to find the centre distance for a target belt length, solving the equation numerically. Diameters and distances accept millimetres, centimetres, metres, inches or feet, and lengths are reported in several units. Everything is computed locally and deterministically, so it is instant and private. Ideal for machine and drivetrain design tools, maintenance and MRO apps, maker and CNC projects, and mechanical-engineering calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is belt-and-pulley power transmission; for bicycle gear ratios and development use a bike-gear API and for bolt tightening torque use a torque API.
api.oanor.com/beltdrive-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 80 ms
- Server probes · 24h
- Subscribers
- 4,956
- active
- Total calls
- 76
- last 7 days
Pricing
Pick a tier — billed monthly, cancel anytime.
Free
Free
- 13,935 calls / month
- 2 requests / second
- Hard cap (429 above quota, no overage)
- 13,935 calls/month
- 2 req/sec
- Belt length + ratio + centres
- No credit card
Starter
€15.55 /month
- 23,650 calls / month
- 8 requests / second
- Hard cap (429 above quota, no overage)
- 23.65k calls/month
- 8 req/sec
- Wrap angles, belt speed
- Email support
Pro
€35.85 /month
- 286,500 calls / month
- 20 requests / second
- Hard cap (429 above quota, no overage)
- 286.5k calls/month
- 20 req/sec
- Machine / drivetrain pipelines
- Priority support
Mega
€73.85 /month
- 1,475,000 calls / month
- 50 requests / second
- Hard cap (429 above quota, no overage)
- 1.475M calls/month
- 50 req/sec
- Platform scale
- Dedicated SLA
Built by
Related APIs
Other APIs with overlapping tags.
Pulley System API
Pulley and block-and-tackle mechanics as an API, computed locally and deterministically. The advantage endpoint computes the mechanical advantage of a pulley system — the ideal MA equals the number of rope parts supporting the load, which is also the velocity ratio — and returns the effort needed to hold or raise a load, effort = load/(n·efficiency), the length of rope that must be pulled (n times the lift height) and the work in and out. The friction endpoint models a real block and tackle where every sheave loses a little tension: the mechanical advantage becomes MA = e·(1−eⁿ)/(1−e) for a per-sheave efficiency e (≈0.96 for a plain bearing, ≈0.98 for a ball bearing), so it returns the true MA, the overall efficiency and the extra effort friction costs you. The solve endpoint takes any two of the load, the effort and the number of rope parts and returns the third — for example, how many parts you need so a given person can raise a given load, or the heaviest load a winch can lift. Everything is computed locally and deterministically, so it is instant and private. Ideal for rigging, lifting and hoist-design tools, sailing, climbing and theatre-rigging apps, crane and winch sizing, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is pulley and block-and-tackle mechanics; for lever and moment balance use a lever API and for rope-around-a-drum capstan friction use a capstan API.
api.oanor.com/pulley-api
Riveted Joint API
Riveted-joint strength maths as an API, computed locally and deterministically — the shear, bearing and rivet-count numbers a structural, sheet-metal or aircraft fitter checks a riveted connection by. The shear-capacity endpoint gives the load a rivet group carries across its shanks = the rivet area (π/4·d²) × the shear strength × the number of rivets × the shear planes — a rivet in single shear is cut on one plane, in double shear (the centre plate of a butt joint with cover plates) on two, so it carries twice. The bearing-capacity endpoint gives the load the rivets can press against the sides of their holes before the plate crushes = the projected contact area (diameter × plate thickness) × the bearing strength × the number of rivets; thin plates fail in bearing long before the rivet shears, which is exactly why both must be checked — the joint strength is the lesser of the two. The rivets-required endpoint inverts it: the rivets a design load needs = the load ÷ the allowable load per rivet (area × allowable shear × planes), rounded up to a whole rivet, using the working shear (strength ÷ safety factor) not the raw value. Everything is computed locally and deterministically, so it is instant and private. Ideal for structural and sheet-metal estimating, mechanical-design and fastener tools, and engineering calculators. Pure local computation — no key, no third-party service, instant. Shank-shear and bearing only — also confirm edge tear-out and minimum pitch. 3 compute endpoints. For bolt preload and torque use a bolt-torque API; for thread geometry a thread API; for welded joints a welding API.
api.oanor.com/rivet-api
Winch Drum API
Winch and cable-drum maths as an API, computed locally and deterministically — the rope-capacity, line-pull and rope-out numbers a winch operator, rigger or recovery driver works a drum with. The capacity endpoint gives the rope a drum holds by exact layer geometry: the sum over every full layer of the turns per layer × π × that layer's mean wrap diameter, where turns per layer = drum width ÷ rope diameter and the number of layers = the flange-to-barrel depth ÷ rope diameter — a 10-inch barrel, 20-inch flange, 12-inch-wide drum on half-inch rope holds about 940 ft over 10 layers. The layer-pull endpoint shows why pull falls as the drum fills: the rated pull is for the bare-drum first layer, and as rope piles on, the growing lever arm cuts the line pull and raises the line speed in the same ratio — pull × (first-layer diameter ÷ this layer's diameter) — so the top layer of a deep drum can pull barely half the bottom-layer rating, which is why you spool off to bare drum for a hard pull or add a snatch block. The length-at-layer endpoint gives the rope wound after a number of full layers, for marking the rope or knowing how much line is out. Everything is computed locally and deterministically, so it is instant and private. Ideal for winch- and hoist-sizing tools, recovery and off-road apps, marine and industrial-rigging utilities, and engineering calculators. Pure local computation — no key, no third-party service, instant. Geometric estimate — allow for nesting and freeboard. 3 compute endpoints. For capstan friction use a capstan API; for block-and-tackle a pulley API.
api.oanor.com/winch-api
Elevator Traction API
Traction-elevator engineering maths as an API, computed locally and deterministically — the counterweight, hoist-motor and rope-traction numbers a lift engineer or building-services designer sizes a passenger elevator with. The counterweight endpoint gives the balancing mass = the empty car plus a fraction of the rated load (the overbalance, typically 40–50 %, 45 % common), so a 1,000 kg car rated for 1,000 kg uses a 1,450 kg counterweight — the car and weight balance near half load and the machine is sized for the worst-case imbalance, not the full load. The motor-power endpoint uses that: because the counterweight cancels most of the car, the motor only lifts the out-of-balance load = rated load × (1 − overbalance), so power = that × g × speed ÷ efficiency (~65–75 % geared) — a 1,000 kg lift at 1.5 m/s needs only about 11–12 kW, half what a counterweight-less hoist would draw. The traction-ratio endpoint checks the friction grip: a traction elevator moves the ropes by friction over the sheave, so the available traction (e^(μθ), the capstan equation) must beat the T1/T2 tension ratio at both worst cases — a full car at the bottom and an empty car at the top — and it returns the governing ratio. Everything is computed locally and deterministically, so it is instant and private. Ideal for lift-design and building-services tools, vertical-transport and MEP utilities, and engineering calculators. Pure local computation — no key, no third-party service, instant. Sizing estimates — follow the lift code and maker data. 3 compute endpoints. For block-and-tackle use a pulley API; for capstan friction a capstan API.
api.oanor.com/elevator-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for Belt Drive API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Belt Drive API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Belt Drive 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 Belt Drive API cost?
Belt Drive API has a free tier with 100 calls / month. Paid plans start at €15.55 / 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 Belt Drive API GDPR-compliant?
All requests to Belt Drive 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.
Pick an endpoint from the list on the left to see its details and try it.
Code snippets
Sign up to get an API key, then call any path under your slug.
curl https://api.oanor.com/beltdrive-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/beltdrive-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/beltdrive-api/SOME_PATH");
curl_setopt($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/beltdrive-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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