1. What is a Bike Speed Calculator by Gear Ratio?

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 rotational motion to linear speed, accounting for gear reduction and tire circumference.

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 optimal for endurance riding.

Q2: How do I measure tire diameter?
A: Check the tire sidewall for size markings (e.g., 700x25c) or measure from ground to axle and double it.

Q3: What's a common gear ratio?
A: Road bikes often have 2.5-4.5 ratios, while mountain bikes range 1.5-3.5 depending on terrain.

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

Q5: Does this account for hills or wind resistance?
A: No, this calculates theoretical speed on flat ground with no resistance factors.