Gear Speed Calculator by Tons of Concrete

Gear Speed Formula:

\[ S = \frac{Cadence \times GR \times WheelCirc}{60} \]

Speed (km/h):

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1. What is a Gear Speed Calculator?

Definition: This calculator estimates the speed of a vehicle or bicycle based on cadence (RPM), gear ratio, and wheel circumference.

Purpose: It helps cyclists, mechanics, and engineers determine speed under different gearing conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ S = \frac{Cadence \times GR \times WheelCirc \times 3.6}{60} \]

Where:

\( S \) — Speed (km/h)
\( Cadence \) — Rotations per minute (rpm)
\( GR \) — Gear ratio (unitless)
\( WheelCirc \) — Wheel circumference (meters)

Explanation: The formula converts rotational motion to linear speed, with the 3.6 factor converting m/s to km/h.

3. Importance of Gear Speed Calculation

Details: Proper speed estimation helps in gear selection, performance optimization, and mechanical efficiency analysis.

4. Using the Calculator

Tips: Enter cadence (typical cycling cadence is 60-100 rpm), gear ratio (chainring teeth ÷ cog teeth), and accurate wheel circumference. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I measure wheel circumference?
A: Measure the distance the wheel travels in one complete revolution, or calculate using π × diameter.

Q2: What's a typical gear ratio for bicycles?
A: Common ratios range from 2.0 (easy gear) to 5.0 (hard gear), depending on chainring and cog sizes.

Q3: Why multiply by 3.6 in the formula?
A: This converts meters per second to kilometers per hour (1 m/s = 3.6 km/h).

Q4: Can I use this for vehicles other than bicycles?
A: Yes, it works for any gear-driven vehicle if you know the cadence (engine RPM), gear ratio, and wheel circumference.

Q5: How accurate is this calculator?
A: It provides theoretical speed. Actual speed may vary due to factors like tire slip, wind resistance, and terrain.