Bicycle Gear & Speed Calculator
Free simulator to instantly calculate gear ratio, speed (km/h), and development per pedal stroke by entering chainring teeth, cog, cadence, and tire size.
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About Bicycle Gear Calculator
The Bicycle Gear Ratio & Speed Calculator is a free tool to easily find the optimal gear settings for your road, cross, or mountain bike (MTB). Just enter the chainring and cog teeth, tire size, and cadence to instantly calculate the gear ratio and speed.
It is highly useful when considering a new sprocket or planning the best gear setup for races and hill climbs. You can also calculate the development per pedal stroke to intuitively grasp how heavy the gear feels.
All calculations are performed on your browser, and no input data is sent to external servers. It is completely safe and secure to use from both PCs and smartphones.
How to Calculate Gear & Speed
Enter Teeth and Tire
Select or input your front chainring teeth, rear cog teeth, and the tire size of your bicycle.
Set Cadence
Enter your expected pedal revolutions per minute (cadence). Typically, 80-90 rpm is standard.
Check Results
The gear ratio, speed (km/h), and distance per pedal stroke are automatically calculated. You can adjust the numbers to run different simulations.
Bicycle Drivetrain Glossary
- Gear Ratio
- The number of front teeth divided by the rear teeth. It represents how many times the rear wheel turns for one pedal revolution. A higher number means heavier pedaling and more speed, while a lower number makes climbing hills easier.
- Cadence
- The number of times the pedals rotate per minute, expressed in rpm. For road bikes, 80-100 rpm is generally considered efficient.
- Chainring
- The front gear attached to the pedals. It is expressed in teeth (e.g., '50T'). More teeth mean heavier pedaling.
- Sprocket/Cog
- The rear gear attached to the back wheel. A set of multiple gears is called a cassette. More teeth mean lighter pedaling.
- Tire Circumference
- The distance the tire travels in one full rotation. It varies by tire diameter and width (e.g., 700x25C) and is crucial for speed calculation.
FAQ
- Q.What is the optimal gear ratio for beginners?
- For flat roads, start with a gear ratio around 2.0 to 2.5 and adjust according to your leg strength and cadence. For steep climbs, having a light gear ratio near 1.0 (e.g., 34T front, 32T rear) is safe.
- Q.What cadence should I aim for?
- For casual cycling or touring, 70-80 rpm is ideal. For sports riding or road bike training, maintaining 80-100 rpm is considered efficient and less fatiguing.
- Q.Can I calculate using a special tire size not on the list?
- Currently, we offer common presets, but we plan to add a custom setting feature that allows you to directly input the tire circumference in millimeters.
- Q.Why does the calculated speed differ from actual speed?
- The result is a theoretical value that does not account for air resistance, tire deformation from pressure, rider weight, or road conditions. Actual speeds may vary.
- Q.Is the data I enter saved on a server?
- No, nothing is saved. All calculations run locally in your browser. Input data and results are never sent to external servers, protecting your privacy.
Use Cases of Simulator
🏔️ Hill Climb Gear Setup
Before a race or touring a steep pass, simulate what speed a light gear ratio (e.g., 34T x 32T) will yield while maintaining your cadence.
🛒 Comparing Sprockets
When buying a new cassette or chainring, check in advance how your top speed and pedaling weight will change.
🚴 Setting Training Goals
Calculate backwards to find out what cadence is required with your current gear ratio to reach a specific speed (e.g., 35 km/h) for training targets.
⚙️ Single Speed Selection
When building a fixie or single-speed bike, easily calculate the best gear ratio for city riding and the distance per pedal rotation.
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