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Gearratio

Gear inches, development, speed-at-cadence and full cassette/chainring comparison from real wheel-size standards

Unify Dynamics LLC

Documentation
Tools3read-only
Sign-inNoneno account, no key
Data keptNoneprocessed in memory
PriceFreeoptional Pro limits
StatusLiveMCP + REST
Works withMCP · RESTany agent

Try asking

Real questions, and the tools your agent calls to answer them.

Gear inches for a 50/17 on 700x25c
Tools called
gear_metrics
Speed at 90rpm in a 52x11 on 700x25c
Tools called
speed_table
Compare my 34/50 chainrings against an 11-32 cassette
Tools called
gear_comparison
Development in meters for a 40x20 on 26-inch wheels
Tools called
gear_metrics

About

Gearratio computes real cycling gear-ratio geometry. gear_metrics gives gear ratio, gear inches, and development (metres travelled per pedal revolution) for one chainring/cog/wheel combination, computed from the wheel's real ISO 5775/ETRTO bead-seat diameter (700C = 622mm, 650B = 584mm, 26-inch MTB = 559mm, 29er) plus tire width. speed_table gives the resulting road speed in km/h and mph across a 60-110rpm cadence range. gear_comparison runs every combination across a list of chainrings and a cassette's cogs, sorted low to high, with the overall gear-range ratio. Keyless; computed locally from real circumference and gear-ratio formulas; nothing stored.

Sources: Computed locally from ISO 5775/ETRTO bead-seat diameters and standard gear-inch/development/speed formulas; fully local, zero upstream calls

Privacy

The publisher, Unify Dynamics LLC, states that tool inputs are processed in memory and not retained.

Data not collectedNo account, no profile, no stored prompts or results.
Privacy policyTerms

What it can do

3 tools, grouped by job. Every one is read-only or compute-only.

OpenAPI
One gear2 tools
  • Gear metricsGear ratio, gear inches, and development (metres per pedal revolution) for one chainring/cog/wheel combination, computed from the wheel's real…
  • Speed tableRoad speed (km/h and mph) across a cadence range (60-110 rpm) for one chainring/cog/wheel combination.
Full range1 tools
  • Gear comparisonGear ratio, gear inches, development and speed-at-cadence for every chainring x cog combination across a full cassette/chainring range, sorted low…

Information

PublisherUnify Dynamics LLC
CategorySports & fitness
LanguagesEnglish
Built forGlobal (metric and imperial wheel/tire conventions)
CompatibilityAny MCP client · any agent · REST
Version0.1.0
MCP endpointhttps://gearratio.connectorbay.com/mcp
REST APIopenapi.json
SupportGet help · Status
CountryWorldwide

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Documentation

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What Gearratio is for

"What gear am I actually in, and how fast does that translate to at my cadence?" — real gear-inches, development, and speed math for a chainring/cog/wheel combination, plus a full comparison across every gear a cassette offers.

What it does

gear_metrics computes gear ratio, gear inches, and development (metres travelled per single pedal revolution) for one chainring/cog/wheel combination, from the wheel's real ISO 5775/ETRTO bead-seat diameter (700C = 622mm, 650B = 584mm, 26-inch MTB = 559mm) plus tire width. speed_table gives the resulting road speed (km/h and mph) across a cadence range (60-110 rpm). gear_comparison runs every combination across a list of chainrings and a cassette's cogs, sorted low to high, with the overall gear-range ratio (highest ÷ lowest) — the full spread a bike actually offers, not just one gear.

What it is not

Not a bike fit or component-compatibility check: it doesn't know whether a given chainring/cassette/derailleur combination is mechanically compatible, only the resulting geometry. Wheel outer diameter is approximated from the standard bead-seat diameter plus twice the tire width (a roughly circular tire cross-section), the same approximation classic gear calculators use without a measured rollout — for a precise number, measure your actual wheel's rollout circumference and use the closest tire-width setting to match it.

Privacy policy

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Gearratio — Privacy Policy

Effective 28 September 2026. Unify Dynamics LLC ("we", "us"), Menlo Park, California.

What Gearratio is. Gearratio is a connector (an MCP server and REST API) that AI assistants and personal agents call on your behalf for cycling gear-ratio math. You interact with your assistant; the assistant sends us only the tooth counts, wheel standard, tire width and cadence needed for the calculation.

What we receive. The arguments of each tool call — chainring and cog tooth counts, a wheel standard, an optional tire width, an optional cadence, and lists of chainrings/cogs for a comparison — the technical headers needed to serve the request (an IP address or a client identifier supplied by the assistant, and a Pro API key if you have one), and standard server logs.

Everything is computed on our server and nothing is stored. The wheel standards are bundled constants; the calculators are formulas. No request is forwarded to any third party. Numbers you send are used for that one answer and are not recorded, logged in request bodies, linked to any identity, or used to train anything.

What we do not receive or store. We do not receive your conversation with the assistant, your name, contacts, or any account records. Rate-limit counters (a client identifier and timestamps) are held in memory for at most 24 hours. Hosting-provider access logs, which contain IP addresses and request paths but not request bodies, are retained for up to 30 days for security and abuse prevention.

Sub-processors. None. Hosting: Vercel (United States regions).

Legal bases and your rights. For users in California, the EU/UK and elsewhere, our processing is necessary to provide the service you request through your assistant. Because we store no personal data beyond short-lived logs, requests to access, correct or delete personal data are usually satisfied automatically; you can still contact agent@connectorbay.com and we will respond within 30 days. We do not sell or share personal information and do not use your data to train models.

Changes. We will post changes here with a new effective date.

Terms of service

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Gearratio — Terms of Service

Effective 28 September 2026. These terms govern use of the Gearratio connector ("the Service") operated by Unify Dynamics LLC ("we", "us").

  1. The Service. Gearratio computes cycling gear-ratio geometry — gear inches, development, speed-at-cadence, and cassette/chainring comparison tables — from tooth counts and standard wheel-size geometry (ISO 5775/ETRTO bead-seat diameters). It is accessed through an AI assistant or directly over MCP or HTTP.
  2. Sources. Bead-seat diameters (700C = 622mm, 650B = 584mm, 26-inch = 559mm) are the published ISO 5775/ETRTO standard; rolling (outer) diameter is approximated from the bead-seat diameter plus twice the tire width, the same approximation classic gear calculators use without a measured rollout. Gear-inch, development and speed formulas are standard, long-used cycling definitions.
  3. Informational only. Output is geometric computation, not a mechanical compatibility check or a fit assessment; verify component compatibility (chain length, derailleur capacity, frame clearance) separately.
  4. Acceptable use. Do not use the Service to circumvent rate limits. Automated use within the published limits is welcome.
  5. Availability. The Service is provided "as is" without warranty. We may change, limit or discontinue it at any time.
  6. Data. Our Privacy Policy describes what we process. In short: your query is answered on our server and nothing is stored.
  7. Pro keys. Optional Pro API keys are issued at our discretion, are personal to the holder and may be revoked for abuse.
  8. Liability. To the fullest extent permitted by law, Unify Dynamics LLC is not liable for any loss arising from use of or reliance on the Service. Our total liability is limited to US $100.
  9. Governing law. California law; venue in San Mateo County, California.
  10. Contact. Unify Dynamics LLC · agent@connectorbay.com · https://connectorbay.com/gearratio

Support

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Gearratio support

Email agent@connectorbay.com. We answer within two business days.

When you report a problem, include the question you asked your agent, roughly when, and which agent you used (for example Claude, ChatGPT or Gemini). Never send us passwords, account numbers or ID numbers. Gearratio never asks for them.

Get Gearratio

Free · No sign-in · Read-only

Streamable HTTP, stateless, no authentication. Paste the endpoint into any MCP-capable agent.

https://gearratio.connectorbay.com/mcp
{
  "mcpServers": {
    "gearratio": {
      "type": "http",
      "url": "https://gearratio.connectorbay.com/mcp"
    }
  }
}