Offline drivetrain workshop
Spin the driving sprocket, change the teeth, and watch ratio, cadence, speed and chain links update live. Try the real thing below, no signal needed.
Touch-to-spin drivetrain with real-time velocity physics and a dynamic chain mesh from 10T to 60T.
Exact gear ratios plus cadence-to-speed output, such as 50T over 11T equals 4.55.
Required pitch links from center distance and tooth counts, every time.
Store gear combinations for tracks, terrains and bikes, all 100% offline.
⚙️ We are a small crew of riders, kart mechanics and robotics tinkerers who got tired of scribbling tooth counts on grease-stained napkins. GearRatio grew out of the garage bench.
🎯 Our mission is simple: make drivetrain matching clear and stress-free for cyclists, racers, builders and engineers, wherever the work happens.
🔧 The app gives you a spinning sprocket simulator, an RPM and speed scaler, rollout and gear-inch math, an exact chain link estimator and a vault for your favorite setups, all without a cellular connection.
Right ratio. Right chain. Right now.
Effective Date: September 2026
GearRatio: Sprocket & Chain does not collect, store or share any data. Everything happens locally on your device.
None. The app does not ask for, record or transmit personal information, usage statistics, location or device identifiers. Tooth counts, center distances and tire sizes you enter stay with you.
Since we hold no information, we do not use, analyze, profile or sell it. Calculations such as ratios, RPM scaling, rollout and chain links are performed on your device only.
Setups saved in the Drivetrain Setup Vault live only in local storage on your device. There is no cloud, no server and no sync, so the app works fully offline.
We integrate no third-party analytics, advertising networks, social plugins or trackers. Nothing in the app talks to an outside service.
Because data never leaves your device, there is no transmission to intercept and no remote database to breach. Local data is protected by your device's own security features.
The app is friendly to young users and consistent with COPPA principles: we collect no data from anyone, including children under 13.
There are no accounts to manage. Clear saved setups in the app, or delete the app to remove all locally stored data at once.
If this policy changes, we will update this page and revise the effective date. Our core commitment of collecting nothing will remain.
Questions? Write to privacy@gearratiosprocketchainapp.com.
👋 Got a question, a feature idea or a wild gear setup to share? We would love to hear from you.
⏱️ We usually reply within 24 to 48 hours.