A precision drivetrain calculator for road cyclists, track racers, and mechanics who'd rather trust the math than a sensor. Count teeth, set your RPM, know your speed — no server, no signal, no subscription.
Everything a mechanical mind needs to spec a drivetrain, from the workshop vise to the start line.
Enter front chainring and rear cog teeth and get your exact gear ratio and rollout distance per pedal stroke, instantly.
Combine ratio, wheel circumference, and target RPM to project real-world speed before you ever clip in.
Keep a clean, fully local archive of your favorite gear combinations, tagged with notes for shifting terrain.
Crisp haptic feedback confirms every calculation and every ledger wipe — built for fast, trackside entries.
Drag the teeth counts and RPM below — the gears and readout update in real time, same math as the app.
We're a small crew of gear-obsessed mechanics, track racers, and weekend tinkerers who got tired of eyeballing chainring math on a greasy workbench. Check 2 Rider: Cadence Calc grew out of that frustration — a tool built by people who actually count teeth for a living, not a generic fitness app with a bike icon slapped on top.
Our mission is simple: put real drivetrain engineering in your pocket without asking you to trust a cloud server, a Bluetooth sensor, or a subscription. Every formula here is the same one a frame builder or track mechanic would scratch onto a notepad — we just made it faster, offline, and exact.
Inside, you'll find a Drivetrain Ratio Matrix to turn chainring and cog counts into a clean gear ratio and rollout distance, a Cadence Velocity Calc that pairs your ratio with wheel circumference and target RPM, and a Mechanical Setups Ledger so your favorite combinations are always one tap away.
No accounts, no signal, no guessing. Just the math, exactly where you need it.
Check 2 Rider: Cadence Calc was built on one principle: your data is your business, not ours. This policy explains — plainly — what that means in practice.
We collect nothing. There are no user accounts, no names, no email addresses, no location data, and no usage analytics gathered by this app. Every gear ratio, cadence figure, and ledger entry you type — chainring teeth, cog counts, wheel circumference, target RPM, and setup notes — is entered by you and stored only on your own device.
Since nothing is collected, nothing is used, analyzed, sold, or shared. Every calculation, from ratio math to velocity projections, is performed entirely on your device, in real time, with no data ever leaving your phone or tablet.
Any gear configurations or notes you save in the Mechanical Setups Ledger are stored locally on your device only. There is no cloud sync, no remote database, and no server that ever receives or holds your information.
This app does not integrate third-party analytics, advertising networks, tracking pixels, or external SDKs of any kind. There are no hidden scripts phoning home in the background.
Because your information never leaves your device, there's no transmission to intercept and no external server to breach. Your device's own security — passcode, biometric lock, encryption — is your primary safeguard, and we recommend keeping it enabled.
We do not knowingly collect information from anyone, including children under 13. Since no personal data is gathered from any user regardless of age, this app is designed to be compliant with COPPA by design, not by exception.
You are always in full control of your data. Every ratio, setup, and note lives only in local app storage. Deleting the app permanently removes all associated data — there are no backups, no linked accounts, and no remote copies anywhere.
We may update this policy periodically to reflect new features or clarify existing language. Any changes will be posted here with a revised effective date at the top of this page.
Questions about this policy can be sent to privacy@check2ridercadencecalcapp.com.
👋 Got a question, a bug to report, or a gear ratio that doesn't add up? We'd love to hear from you. Whether you're troubleshooting a calculation, suggesting a feature for the next build, or just want to talk about your favorite drivetrain setup, drop us a line.