Gear Ratio Calculator

Understanding Gear Ratios

A bike's gear ratio is calculated by dividing the number of teeth on the front chainring by the number of teeth on the rear cog. A higher ratio means harder pedaling but more speed potential, while a lower ratio makes pedaling easier but limits top speed.

Gear Inches is a traditional way to measure gear size, taking into account both the gear ratio and wheel size. It represents the diameter of an equivalent direct-drive wheel (like on a penny-farthing bicycle).

Gear Visualization

Speed at Different Cadences

Gear Combinations Comparison

Gear Selection Tips

  • Climbing: Use lower gear ratios (smaller chainring, larger cog) for easier pedaling up hills.
  • Flat Terrain: Middle range ratios provide a good balance of speed and effort.
  • Descending: Higher ratios (larger chainring, smaller cog) allow you to maintain power at higher speeds.
  • Cadence: Most cyclists find a cadence of 80-100 RPM efficient for sustained riding.
  • Cross-Chaining: Avoid extreme combinations (largest-largest or smallest-smallest) to reduce wear.

Optimal Gear Ratios for Different Scenarios

  • Racing: Higher ratios (2.5-4.0) for maximum speed potential
  • Commuting: Medium ratios (2.0-3.0) for versatility
  • Mountain Biking: Lower ratios (1.5-2.5) for technical terrain
  • Touring: Wide range of ratios (1.5-3.5) for varied conditions
Note: Actual speeds may vary due to factors such as tire pressure, rider weight, wind resistance, road conditions, and gradient. This calculator provides theoretical values based on ideal conditions. For optimal performance, consider these factors and adjust your gearing based on personal experience and riding conditions.