{"uid":"cap_8AFRQQBMGK90aOpRr4WGx","slug":"bicycle-gear-ratio-speed-calculator-5066c7ba","name":"Bicycle Gear Ratio & Speed Calculator","description":"Gear ratio, gear inches, development per pedal turn and speed at a cadence for a chainring and cog on a given wheel.","url":"https://bike-calc.x402tookit.com/gear-ratio?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["chainring","cog"],"properties":{"cog":{"type":"integer","description":"Rear cog teeth (for example 17)"},"wheel":{"type":"string","description":"Tyre preset: 700x23c, 700x25c, 700x28c, 700x32c, 700x35c, 700x38c, 26x2.0 (default 700x25c)"},"cadence":{"type":"number","description":"Pedalling cadence in rpm (default 90)"},"chainring":{"type":"integer","description":"Chainring teeth (for example 50)"},"diameterInches":{"type":"number","description":"Wheel diameter in inches instead (for example 26 for a 26 inch wheel)"},"circumferenceMm":{"type":"number","description":"Rolling circumference in mm instead of a preset (measure it on the bike)"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"cog":{"type":["null","number"]},"asOf":{"type":["null","string"]},"ratio":{"type":["null","number"]},"source":{"type":["null","string"]},"reasons":{"type":["array","null"],"items":{"type":"string"}},"summary":{"type":["null","string"]},"verdict":{"type":["null","string"]},"degraded":{"type":["boolean","null"]},"speedKmh":{"type":["null","number"]},"speedMph":{"type":["null","number"]},"chainring":{"type":["null","number"]},"cadenceRpm":{"type":["null","number"]},"disclaimer":{"type":["null","string"]},"gearInches":{"type":["null","number"]},"notChecked":{"type":["array","null"],"items":{"type":"string"}},"circumferenceMm":{"type":["null","number"]},"metersPerMinute":{"type":["null","number"]},"developmentMeters":{"type":["null","number"]},"wheelDiameterInches":{"type":["null","number"]}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_IgZX52dVtfKMTp4vxxxvu","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates gear ratio, gear inches, development per pedal turn, and speed at a given cadence for a specific chainring and cog combination on a bicycle wheel.","exampleAgentPrompt":"What gear ratio, gear inches, and speed will I get at 90 rpm with a 50-tooth chainring and a 17-tooth cog on 700x25c tyres?","exampleUseCases":[{"title":"Road bike high gear speed check","prompt":"I'm running a 53 chainring and an 11-tooth cog on 700x25c wheels — what's my gear ratio, gear inches, and how fast will I be going if I'm spinning at 95 rpm?"},{"title":"Fixed gear urban commuter setup","prompt":"For a fixed gear bike with a 44-tooth chainring and a 16-tooth cog on 700x23c tyres, what's the gear development in meters per pedal stroke and my speed at 85 rpm?"},{"title":"Gravel bike climbing gear analysis","prompt":"What are the gear inches and speed for a 34-tooth chainring paired with a 32-tooth cog on 700x38c gravel tyres at a cadence of 75 rpm?"}],"resultDescription":"Returns the gear ratio (chainring/cog), gear inches (effective wheel diameter driven per crank revolution), development in meters (distance per pedal stroke), speed in both km/h and mph at the specified cadence, meters per minute, and the wheel circumference and diameter used in the calculation.","failureModes":["Missing required chainring or cog parameters returns an error","Non-integer chainring or cog values cause validation failure","Unrecognised tyre preset string falls back to default 700x25c or may error","Cadence of 0 or negative values may produce nonsensical speed outputs","Providing both diameterInches and circumferenceMm may cause ambiguity — only one override should be used"],"whenToPreferThis":"Use this endpoint when you need precise single-gear-combination calculations including gear ratio, gear inches, development, and speed at cadence. It is ideal for evaluating a specific chainring/cog pairing before a ride or when building a gear recommendation tool. Prefer the full drivetrain matrix endpoint (sibling) if you need all combinations across a cassette at once.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T13:13:43.173Z","isFirstParty":false,"canonicalSlug":"bicycle-gear-ratio-speed-calculator-5066c7ba"}