1. What Is the Bike Speed Calculator?

Definition: This calculator estimates your current bike speed based on pedaling rate (RPM), tire size, and gear ratio.

Purpose: Helps cyclists understand their speed potential at different cadences and gear combinations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Speed (mph)
• \( RPM \) — Pedal revolutions per minute
• \( TD \) — Tire diameter (inches)
• \( GR \) — Gear ratio (chainring teeth ÷ cog teeth)
• \( 1056 \) — Conversion factor (combines unit conversions)

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

3. Importance of Bike Speed Calculation

Details: Understanding this relationship helps with gear selection, training at specific speeds, and optimizing pedaling efficiency.

4. Using the Calculator

Tips: Measure your tire diameter accurately (printed on sidewall or measure from ground to axle × 2). Gear ratio is front chainring teeth divided by rear cog teeth.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical road bike gear ratio?
A: Common ratios range from 2.0 (39x19) to 4.0 (52x13), with higher ratios for faster speeds.

Q2: How do I find my tire diameter?
A: Check the tire sidewall (e.g., "700x25c" is about 26.6" diameter) or measure from ground to axle and double it.

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

Q4: Why does the formula include 1056?
A: This converts inches per minute to miles per hour (12 in/ft × 5280 ft/mile ÷ 60 min/hour ≈ 1056).

Q5: Does this account for tire pressure or rider weight?
A: No, this calculates theoretical speed. Actual speed may vary due to tire deformation, wind, and other factors.