1. What is Gear Inches?

Gear inches is a system that expresses bicycle gear ratios in terms of the diameter of an equivalent directly driven wheel. It helps cyclists compare different gear combinations across various bicycles.

2. How Does the Calculator Work?

The calculator uses the Mike Sherman formula:

Where:

• Gear ratio — The ratio of chainring teeth to cog teeth
• Wheel diameter — The diameter of the bicycle wheel in inches

Explanation: The formula calculates the equivalent diameter of a directly driven wheel that would provide the same mechanical advantage as the current gear combination.

3. Importance of Gear Inches

Details: Gear inches allow cyclists to compare different gear setups and choose appropriate gearing for specific terrain or riding conditions. Higher gear inches mean harder pedaling but more speed per pedal revolution.

4. Using the Calculator

Tips: Enter the gear ratio (chainring teeth divided by cog teeth) and the wheel diameter in inches. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical gear inch range for road bikes?
A: Road bikes typically range from 30-120 gear inches, with common cruising gears around 70-90 gear inches.

Q2: How does gear inches relate to cadence and speed?
A: Higher gear inches require more effort to pedal but allow higher speeds at the same cadence. Speed (mph) = (gear inches × π × cadence) / 1056.

Q3: What's a good gear inch for climbing hills?
A: For steep hills, many cyclists prefer gear inches below 50, with some touring bikes going as low as 20 gear inches.

Q4: How do I measure my wheel diameter?
A: Measure from the ground to the center of the axle and multiply by 2, or use standard sizes (e.g., 26", 27.5", 29" for mountain bikes).

Q5: What's the advantage of using gear inches over other systems?
A: Gear inches provide a single number that accounts for both gearing and wheel size, making comparisons between different bikes easier.