Gear Ratio Calculator

- May 12, 2025
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Calculate gear ratios, development, and cadence for bicycles. This calculator helps compare different gear combinations to optimise 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 travelled with one complete rotation of the pedals (in metres).
  • Gear Inches: Traditional measurement representing the diameter of an equivalent direct-drive wheel.
  • Speed at Cadence: How fast you'll go at a given pedalling 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 pedalling.
  • 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.

What Is a Gear Ratio Calculator?

A gear ratio calculator is a handy tool for cyclists. It helps you figure out the ideal gear combinations for your bike. By inputting details like chainring size and rear cog size, you can calculate how these components work together. This information is vital for anyone looking to improve their cycling performance.

Why Gear Ratios Matter

Understanding gear ratios is key to getting the most out of your bike. Here’s why they matter:

  • They determine how far you travel with each pedal stroke.
  • They impact your speed and effort level during rides.
  • They help you tackle various terrains effectively.

Components of the Calculator

The gear ratio calculator takes several inputs to provide accurate results. You’ll need to enter your chainring size, rear cog size, and wheel size. Additionally, you can specify tire width, crank length, and cadence. Each of these factors plays a role in your bike's overall performance.

Finding the Right Gear Combinations

With the gear ratio calculator, you can explore different gear combinations. This allows you to compare how each setup affects your cycling. For example, larger chainrings paired with smaller cogs offer higher speeds, while smaller chainrings with larger cogs make climbing easier. Experiment with different setups to find what works best for you.

Performance Metrics Explained

Aside from gear ratios, the calculator provides various performance metrics. These include:

  • Gear Development: The distance you travel with one complete pedal revolution.
  • Speed at Cadence: How fast you’ll ride at a specific pedaling rate.
  • Gear Inches: A traditional measure of your bike’s gearing efficiency.

Using the Calculator for Different Terrains

Different terrains require different gear setups. On flat roads, higher gear ratios can help you maintain speed. However, when climbing hills, lower gear ratios are more beneficial. By using the calculator, you can determine the best gear ratios based on your riding conditions. This ensures you’re always optimised for your route.

Gear Comparison Features

The calculator also allows for gear comparison. You can assess multiple gear setups side by side. This feature helps you see the differences in gear ratios, development, speed, and more. It’s a great way to visualise how each option will perform, making it easier to choose the best configuration for your needs.

Understanding the Results

Once you've input your data, the calculator gives you results in an easy-to-understand format. You'll see your gear ratio, gear development, speed at cadence, and gear inches. These results can guide your decisions on gear setups. Knowing how each metric impacts your ride helps you become a more informed cyclist.