Sprocket: Bike Gear Calculator
Ratio, Speed & Cadence Tool
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Know your drivetrain before you ride. Live gear ratio, speed & gain ratio — fully offline, zero ads.
Stop guessing — know exactly what every gear combination delivers before you turn a pedal.
Sprocket is the precise bike gear calculator built for road, gravel, MTB, and touring cyclists.
— KEY FEATURES —
• Live calculations: enter front chainring teeth, rear cog teeth, cadence (40–200 rpm), and wheel size — gear ratio, gain ratio, gear inches, and speed in km/h or mph update instantly as you type.
• Six wheel sizes: 700c, 650b/27.5", 29", 26", 24", and 20" — covers road, gravel, mountain, and kids' bikes.
• 10 built-in cassette presets: 11-speed road, gravel, and endurance; 10-speed touring and racing; 12-speed MTB wide-range — full cog-by-cog listings for every preset.
• Custom cassettes: add any cassette by entering a comma-separated cog sequence; the app auto-detects speed count and cog range.
• Saved bike setups: store named setups with chainring, cassette, wheel size, and target cadence. Each setup shows top speed, hardest gear ratio, gear inches, and easiest gear at a glance — perfect for comparing builds before swapping parts.
• 5 seeded setups to explore: Road Racer, Gravel Adventure, Trail MTB, Sprint Track, and Loaded Tourer — realistic starting points for every riding style.
• mph / km/h toggle: flip speed units anywhere in the app without re-entering data.
• Fully offline: no account, no ads, no network connection ever required. Your data lives on-device.
Whether you're speccing a new build, planning a gear swap, or nerding out on drivetrain math, Sprocket gives you the numbers you need — instantly and accurately.
— Sprocket Bike Gears PREMIUM —
Sprocket Premium unlocks the full app experience: unlimited saved bike setups, all 10 cassette presets plus custom cassette entry, and every calculation metric (gear ratio, gain ratio, gear inches, and speed) — completely ad-free and 100% offline.
Subscription options:
• Weekly — $9.99 / week
• Yearly — $49.99 / year (includes a 3-day free trial)
Payment is charged to your Apple Account at confirmation of purchase. Subscriptions renew automatically unless turned off at least 24 hours before the end of the current period. Your account is charged for renewal within 24 hours prior to the end of the period. Manage or cancel anytime in your Apple Account settings.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://pnkl26.web.app/privacy-policy
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Version 1.0
• Live gear ratio, gain ratio, gear inches, and speed calculator (km/h and mph)
• Cadence stepper from 40 to 200 rpm in 5-rpm increments
• Six wheel size options: 700c, 650b/27.5", 29", 26", 24", 20"
• 10 built-in cassette presets covering road, gravel, MTB, and touring drivetrains
• Custom cassette entry via comma-separated cog sequence
• Save and manage named bike setups with hardest/easiest gear summary
• 5 seeded setups: Road Racer, Gravel Adventure, Trail MTB, Sprint Track, Loaded Tourer
• Fully offline — no account or network required
The developer, Linh Phan Nhat Khanh, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Linh Phan Nhat Khanh
- Size
- 719.9 KB
- Category
- Sports
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Sprocket Bike Gears Yearly $49.99
- Sprocket Bike Gears Weekly $9.99
- Copyright
- © 2026 PNKL