1. What is a Bicycle Gear Inch Calculator?

Definition: This calculator determines the gear inches of a bicycle, which is a measure of the mechanical advantage of the drivetrain.

Purpose: It helps cyclists compare gear ratios across different wheel sizes and understand their bike's gearing.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( GI \) — Gear inches (inches)
• \( GR \) — Gear ratio (front chainring teeth ÷ rear cog teeth)
• \( WD \) — Wheel diameter (inches)

Explanation: The gear ratio multiplied by the wheel diameter gives the equivalent diameter of the drive wheel if the bike were direct-driven.

3. Importance of Gear Inch Calculation

Details: Gear inches help cyclists understand how "hard" or "easy" gears will feel, allowing for better gear selection and bike setup.

4. Using the Calculator

Tips: Enter the gear ratio (front teeth ÷ rear teeth) and wheel diameter (default 27" for standard road bike). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical gear inch range?
A: Road bikes typically range from 30-120 gear inches, while mountain bikes might range from 20-90 gear inches.

Q2: How do I measure wheel diameter?
A: Measure from ground to wheel axle and double it, or check manufacturer specs for your tire size.

Q3: Why use gear inches instead of gear ratio alone?
A: Gear inches account for wheel size, allowing comparison between bikes with different wheel diameters.

Q4: What's a good gear inch for climbing hills?
A: Generally, gear inches below 50 are good for climbing, with lower numbers being easier.

Q5: How does this relate to speed?
A: Higher gear inches mean more distance per pedal revolution, potentially higher speed but requiring more effort.