1. What is Speed From Gear Ratio And RPM Calculator?

Definition: This calculator estimates vehicle speed based on engine RPM, gear ratio, and a conversion constant.

Purpose: It helps automotive enthusiasts and engineers determine vehicle speed at specific RPM points for different gear ratios.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Speed (miles per hour)
• \( RPM \) — Engine revolutions per minute
• \( GR \) — Gear ratio (unitless)
• \( C \) — Conversion constant (default 0.00595)

Explanation: The RPM is divided by gear ratio to get output shaft speed, then multiplied by a constant that accounts for tire size and unit conversions.

3. Importance of Speed Calculation

Details: Accurate speed estimation helps with gear selection, performance tuning, and understanding vehicle behavior at different RPM ranges.

4. Using the Calculator

Tips: Enter the engine RPM, gear ratio, and conversion constant (default 0.00595 for typical tire sizes). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What does the conversion constant represent?
A: It combines tire circumference and unit conversions to transform (RPM/GR) into miles per hour.

Q2: How do I find my gear ratio?
A: Gear ratios are typically listed in vehicle specifications or transmission documentation.

Q3: When would I change the constant?
A: Adjust if using non-standard tire sizes - larger tires increase the constant, smaller tires decrease it.

Q4: Does this work for all vehicles?
A: Yes, but the constant may need adjustment for vehicles with significantly different tire sizes.

Q5: Why is my calculated speed different from actual speed?
A: Differences can come from torque converter slip (automatics), tire wear, or incorrect constant value.