1. What is a Bike Gear Speed Calculator?

Definition: This calculator estimates bicycle speed based on pedaling cadence (RPM), tire diameter, and gear ratio.

Purpose: It helps cyclists understand how different gear combinations affect their speed at various pedaling rates.

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)

Explanation: The formula converts pedal rotations into wheel rotations (via gear ratio) and then into linear distance traveled per minute, which is converted to mph.

3. Importance of Gear Speed Calculation

Details: Understanding this relationship helps cyclists select appropriate gears for desired speeds and maintain efficient pedaling cadences.

4. Using the Calculator

Tips: Enter your pedaling RPM (typically 60-100 for cyclists), tire diameter (common sizes: 26", 27.5", 29"), and gear ratio (front chainring teeth ÷ rear cog teeth).

5. Frequently Asked Questions (FAQ)

Q1: What's a typical cycling RPM?
A: Most cyclists maintain 80-100 RPM, with 90 RPM being a common efficient cadence.

Q2: How do I measure my tire diameter?
A: Check the tire sidewall for size markings (e.g., 26×2.1) or measure from ground to axle center and double it.

Q3: What affects gear ratio?
A: The combination of front chainring size and rear cog size determines your gear ratio (e.g., 50 tooth chainring with 14 tooth cog = 50/14 ≈ 3.57 ratio).

Q4: Why the 1056 constant?
A: This converts inches per minute to miles per hour (12 inches/foot × 5280 feet/mile ÷ 60 minutes/hour = 1056).

Q5: Does this account for rider weight or hills?
A: No, this calculates theoretical speed. Actual speed will vary based on terrain, wind, and rider power.