Gear Ratio Calculator

Category: Sports
- May 14, 2025
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Calculate gear ratios, development, and cadence for bicycles. This calculator helps compare different gear combinations to optimize your cycling performance.

Drivetrain Setup

teeth
teeth
mm
mm

Performance Metrics

rpm

Additional Options

Understanding Gear Ratios

Bicycle gear ratios express the relationship between the number of teeth on the chainring (front) and the cog (rear). This ratio determines how far you travel with each pedal revolution, affecting both speed and effort.

Key Metrics Explained
  • Gear Ratio: Simply the number of teeth on the chainring divided by the number of teeth on the rear cog.
  • Gear Development: The distance traveled with one complete rotation of the pedals (in meters).
  • Gear Inches: Traditional measurement representing the diameter of an equivalent direct-drive wheel.
  • Speed at Cadence: How fast you'll go at a given pedaling rate (cadence).
Choosing the Right Gears

Different riding conditions call for different gear ratios:

  • Flat terrain: Higher gear ratios (larger chainring, smaller cog) allow for greater speed.
  • Hills and climbing: Lower gear ratios (smaller chainring, larger cog) provide easier pedaling.
  • Ideal cadence: Most cyclists find a cadence between 80-100 rpm to be efficient.
  • Closely spaced gears: Smaller jumps between gears allow fine-tuning your effort level.

Gear Ratio Formula:

\[ \text{Gear Ratio} = \frac{\text{Number of Teeth on Chainring}}{\text{Number of Teeth on Rear Cog}} \]

Gear Development:

\[ \text{Gear Development} = \text{Wheel Circumference} \times \text{Gear Ratio} \]

Speed at Cadence:

\[ \text{Speed} = \text{Gear Development} \times \text{Cadence} \times 60 \div 1000 \ (km/h) \]

Gear Inches:

\[ \text{Gear Inches} = \text{Wheel Diameter (in inches)} \times \text{Gear Ratio} \]

What Is the Gear Ratio Calculator?

The Gear Ratio Calculator is a practical tool for cyclists who want to fine-tune their drivetrain setup for speed, efficiency, and comfort. Whether you're on flat roads or steep climbs, this tool provides insights into how your gear choices affect performance.

By entering basic information such as your chainring and cog sizes, wheel dimensions, and pedaling cadence, the calculator estimates key metrics like gear ratio, speed, gear development, and gear inches.

How to Use the Calculator

To get the most from the Gear Ratio Calculator, follow these simple steps:

  • Step 1: Enter your chainring and rear cog sizes in teeth.
  • Step 2: Choose your wheel size from the dropdown list or input a custom diameter.
  • Step 3: Input tire width and crank length to refine the calculation.
  • Step 4: Set your cadence (pedaling speed in revolutions per minute).
  • Step 5: Select your preferred unit system (km/h or mph).
  • Optional: Check the comparison option to analyze multiple gear setups side by side.
  • Step 6: Click “Calculate Gear Ratio” to see your results and charts.

Why This Tool Is Useful

The calculator supports better decision-making when choosing or adjusting bike gears. Here's how it helps:

  • Compare gear combinations before changing components.
  • Visualize how cadence affects speed with interactive charts.
  • Understand how drivetrain setup impacts real-world performance.
  • Find gear setups suitable for commuting, racing, climbing, or touring.

It can be particularly valuable when paired with Other Fitness tools such as a VO2 max estimation app, heart rate zones calculator, or a target heart rate tool to help align your mechanical choices with training goals.

Key Metrics You’ll See

  • Gear Ratio: Indicates how many times the rear wheel rotates per crank revolution.
  • Gear Development: Shows how far the bike travels per full pedal turn (in meters).
  • Speed at Cadence: Predicts your cycling speed at the given cadence.
  • Gear Inches: Used to compare gear setups across different wheel sizes.

Frequently Asked Questions

What is a good gear ratio for climbing?

Lower gear ratios, like 34/28 or 32/32, are better for climbing because they make pedaling easier.

Can I compare multiple gear setups?

Yes, enable the “Compare multiple gears” option to add and evaluate different chainring and cog combinations.

What cadence should I aim for?

Most cyclists find an efficient cadence between 80–100 rpm, though this varies by fitness and terrain.

Is this tool useful for indoor training setups?

Absolutely. It can help replicate outdoor resistance and speed for indoor smart trainer sessions.

Connect with Other Calculators

Cyclists often combine this gear calculator with tools like a 1RM estimate from a One Rep Max Calculator to track strength gains or a race time predictor to plan event pacing. For broader fitness tracking, pairing this with a VO2 max assessment or a running pace guide gives a complete picture of performance.