Spec

Code snippets

curl "https://api.oanor.com/tirecalc-api/v1/meta" \
  -H "x-oanor-key: oanor_test_..."

await fetch("https://api.oanor.com/tirecalc-api/v1/meta", {
  headers: { "x-oanor-key": "oanor_test_..." }
});

$ch = curl_init("https://api.oanor.com/tirecalc-api/v1/meta");
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$out = curl_exec($ch);

import requests
requests.get(
    "https://api.oanor.com/tirecalc-api/v1/meta",
    headers={"x-oanor-key": "oanor_test_..."}
)

Example response

A real response from this endpoint, captured by the latest health check.

{
    "data": {
        "name": "Tire & Drivetrain API",
        "notes": "Sizes are metric (width mm / aspect % R rim-inches). Diameter = rim + 2×sidewall. Speedometer error scales with overall diameter. Nothing is stored.",
        "version": "v1",
        "endpoints": [
            {
                "path": "/v1/tire",
                "params": {
                    "size": "metric tyre size, e.g. 205/55R16"
                },
                "returns": "diameter, circumference, sidewall and revolutions"
            },
            {
                "path": "/v1/compare",
                "params": {
                    "new": "replacement tyre",
                    "speed": "speedometer reading (default 100)",
                    "original": "current tyre"
                },
                "returns": "diameter change and speedometer/odometer error"
            },
            {
                "path": "/v1/gear",
                "params": {
                    "rpm": "& ratio & tire_size (for road speed)",
                    "ring": "& pinion teeth (for a ratio)"
                },
                "returns": "the gear ratio or the road speed"
            },
            {
                "path": "/v1/meta",
                "params": [],
                "returns": "this document"
            }
        ],
        "description": "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 bike/car configurators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is tyre and drivetrain maths; for vehicle specs by VIN use a vehicle-database API."
    },
    "meta": {
        "timestamp": "2026-06-03T17:42:03.105Z",
        "request_id": "1bb3fb99-314d-4939-b45d-9714d816b32e"
    },
    "status": "ok",
    "message": "Meta",
    "success": true
}