1. What is a Gear And Speed Calculator?

Definition: This calculator estimates vehicle speed based on engine RPM, tire diameter, gear ratio, and axle ratio.

Purpose: It helps automotive enthusiasts, mechanics, and engineers determine vehicle speed at specific RPMs with given gear configurations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Speed (miles per hour)
• \( RPM \) — Engine revolutions per minute
• \( TD \) — Tire diameter (inches)
• \( GR \) — Gear ratio (unitless)
• \( AR \) — Axle ratio (unitless)

Explanation: The formula calculates how fast a vehicle will go based on how fast the engine is turning (RPM), the size of the tires, and the gear reduction through the transmission and differential.

3. Importance of Gear and Speed Calculation

Details: Proper gear and speed calculations help optimize vehicle performance, fuel efficiency, and ensure components operate within safe parameters.

4. Using the Calculator

Tips: Enter the engine RPM, tire diameter in inches, gear ratio, and axle ratio. All values must be > 0. The 1056 constant converts inches per minute to miles per hour.

5. Frequently Asked Questions (FAQ)

Q1: How do I measure tire diameter?
A: Measure from the ground to the top of the tire and multiply by 2, or use manufacturer specifications.

Q2: Where can I find my gear and axle ratios?
A: Check your vehicle's manual, manufacturer specifications, or differential/transmission tags.

Q3: Why is the result not matching my actual speed?
A: Variations can occur due to tire wear, inflation pressure, transmission slippage, or converter clutch operation in automatics.

Q4: Can I use this for different transmission types?
A: Yes, but automatic transmissions with torque converters may show slightly different results due to slippage.

Q5: How accurate is this calculator?
A: It provides theoretical speed under ideal conditions. Real-world factors like load, traction, and transmission efficiency may affect actual speed.