1. What is a Bike 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 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 rotation through the gear ratio to wheel rotation, then calculates distance traveled per minute converted to mph.

3. Importance of Gear Ratio Calculation

Details: Understanding gear ratios helps cyclists select appropriate gears for desired speeds and cadences, optimizing performance and efficiency.

4. Using the Calculator

Tips: Enter your pedaling RPM, tire diameter in inches, and gear ratio (chainring teeth ÷ cog teeth). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical cycling RPM?
A: Most cyclists maintain 60-90 RPM, with 80-90 being common for road cycling.

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

Q3: What's a common gear ratio?
A: Varies by bike type - road bikes might use 2.5-5.0, while mountain bikes range 1.5-3.5.

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

Q5: Does this account for real-world factors?
A: No, this is theoretical speed - actual speed may vary due to hills, wind, or tire slippage.