1. What is a Bicycle Gear Ratio Speed Calculator?

Definition: This calculator estimates bicycle speed based on pedal RPM, tire diameter, and gear ratio.

Purpose: It helps cyclists understand how different gear ratios and cadence affect their speed.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Speed (miles per hour)
• \( RPM \) — Pedal revolutions per minute
• \( TD \) — Tire diameter (inches)
• \( GR \) — Gear ratio (unitless)
• 1056 — Conversion factor (inches to miles and hours to minutes)

Explanation: The formula calculates how far the bike travels per pedal revolution based on tire size and gear ratio, then converts this to miles per hour.

3. Importance of Gear Ratio Calculation

Details: Understanding gear ratios helps cyclists optimize their pedaling efficiency for different terrains and riding conditions.

4. Using the Calculator

Tips: Enter your pedal RPM (typically 60-100 for recreational cycling), tire diameter (printed on tire sidewall), and gear ratio (chainring teeth ÷ cog teeth). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical gear ratio for road bikes?
A: Common gear ratios range from 2.0 (easy climbing) to 5.0 (fast downhill), with 3.0-4.0 being typical for flat terrain.

Q2: How do I find my tire diameter?
A: Check the numbers on your tire sidewall (e.g., "700x25c" is about 27 inches diameter).

Q3: What RPM should I aim for?
A: Most cyclists maintain 80-100 RPM for efficient pedaling, but this varies by rider preference.

Q4: Why does tire diameter affect speed?
A: Larger tires cover more ground per revolution, increasing speed for the same RPM and gear ratio.

Q5: How accurate is this calculation?
A: It provides theoretical speed. Actual speed may vary due to factors like wind resistance, tire pressure, and road conditions.