Calculate gear ratios, development, and speed for every cog in your cassette. Optimize gear selection and understand your drivetrain capabilities.
Last updated: March 2026 | By Patchworkr Team
| Style | Ratio Range | Dev @ 90rpm | Use Cases |
|---|---|---|---|
| Climbing | 4.0-5.0 | 9-12m | Mountains, steep |
| Endurance | 5.5-7.0 | 12-16m | Long distance, touring |
| Road (All-purpose) | 7.0-9.0 | 16-20m | Varied terrain |
| Racing | 9.0-12.0 | 20-27m | Speed, flat terrain |
| Sprinting | 12.0+ | 27m+ | Max speed, sprints |
Note: Development = ratio × circumference. Higher = faster but harder; lower = easier climbing.
Gear ratio is the relationship between chainring size (front) and cog size (rear), calculated as Front Teeth ÷ Rear Teeth. A 50/25 gear has a 2.0 ratio—the rear wheel turns twice for every pedal revolution. Higher ratios (3.0+) are for speed, lower ratios (1.5-2.0) are for climbing.
Development (also called "gear inches" in metric) is the distance your bike travels per pedal revolution. It's calculated as Gear Ratio × Wheel Circumference. A 6-meter development means you travel 6 meters forward with each complete pedal stroke. This metric directly translates gearing into real-world distance.
Understanding your full cassette range helps you select the right gear for terrain and cadence preferences. Modern 11-speed cassettes (11-28, 11-32) offer wider ranges than older 8-speed systems, allowing both high-speed sprinting and steep climbing from a single drivetrain setup.
Step 1: Count the teeth on your chainring (front gear). Most road bikes have 50-53t for big ring, 34-39t for small ring. Mountain bikes typically run 28-32t single chainrings.
Step 2: List your cassette cogs separated by commas. Count teeth on each cog, starting from smallest (usually 11t). Common road cassettes: 11-28, 11-30, 11-32. MTB: 11-42, 10-51.
Step 3: Enter your wheel circumference. Standard 700c road wheels: 2.096-2.136m depending on tire width. Measure by marking tire and rolling one full revolution.
Step 4: Set your typical cadence. 80-90 RPM for recreational, 90-100 RPM for competitive cycling. The calculator shows achievable speed at that cadence for each gear.
Setup: Road bike with 50t chainring, 11-28 cassette (11,13,15,17,19,21,24,28), 700×25c wheels (2.1m), maintaining 90 RPM cadence.
Sample Results:
This setup provides a 51.5 km/h top speed (sprint gear) and can climb steep grades at 20 km/h (climbing gear) while maintaining efficient 90 RPM cadence.
1.5-2.0 ratios are ideal for steep climbs. This means small chainring (34t) with large rear cog (28-34t). Allows maintaining 70-80 RPM on 10%+ gradients.
Mark tire and ground with chalk, sit on bike, roll forward one full wheel revolution, measure distance. Standard: 700×23c = 2.096m, 700×25c = 2.105m, 700×28c = 2.136m.
Development is meters traveled per pedal stroke. Higher development = faster but harder. 8-10m is high-speed cruising, 4-6m is climbing, 3-4m is steep technical climbs.
If you struggle on climbs or spin out on descents, yes. Going from 11-28 to 11-32 adds easier climbing gears with minimal weight penalty (~30g).
When different chainring/cog combinations produce the same ratio. Example: 50/19 ≈ 34/13. Not a problem—overlap ensures smooth transitions between gears.
Run the calculator twice—once for each chainring. Compare to see your total range. Compact (50/34) gives wider range than standard (53/39).
These are theoretical speeds at given cadence with no wind/resistance. Real-world speed is 10-20% lower due to aerodynamic drag, rolling resistance, and terrain.
11-28 for flat races, 11-30 for hilly courses, 11-32 for mountainous terrain. Pro racers often choose narrower ranges (11-25) for closer gear spacing on flat stages.
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