Cycling Gear Ratio Speed Calculator

Cycling Speed Formula:

\[ S = \frac{RPM \times \pi \times TD}{GR \times 1056} \]

Cycling Speed (mph):

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1. What is a Cycling Gear Ratio Speed Calculator?

Definition: This calculator estimates cycling 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:

\[ S = \frac{RPM \times \pi \times TD}{GR \times 1056} \]

Where:

\( S \) — Speed (mph)
\( RPM \) — 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 which is converted to mph.

3. Importance of Gear Ratio Calculation

Details: Understanding gear ratios helps cyclists optimize their pedaling efficiency and choose appropriate gears for different terrain.

4. Using the Calculator

Tips: Enter your pedal RPM (typically 60-100 for recreational cycling), tire diameter (marked on your tire), and gear ratio (front chainring teeth ÷ rear cog teeth).

5. Frequently Asked Questions (FAQ)

Q1: What's a typical gear ratio?
A: Road bikes often have ratios from 2.0 (easy gear) to 4.0 (hard gear), while mountain bikes range wider.

Q2: How do I measure tire diameter?
A: Check the tire sidewall for size markings (e.g., "700x25c" is ~27 inches) or measure from ground to axle and double.

Q3: What's a good RPM to maintain?
A: Most cyclists aim for 80-100 RPM for efficient pedaling with reduced fatigue.

Q4: Why does the constant 1056 appear?
A: This 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. Actual speed will be lower due to resistance factors.