1. What is a Larger Tire Size Speed Calculator?

Definition: This calculator estimates the new speed when changing to larger tires based on the original speed and tire diameters.

Purpose: It helps vehicle owners and mechanics understand how tire size changes affect speedometer readings and actual vehicle speed.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S_{\text{new}} \) — New speed (mph)
• \( S_{\text{old}} \) — Original speed (mph)
• \( TD_{\text{large}} \) — Larger tire diameter (inches)
• \( TD_{\text{original}} \) — Original tire diameter (inches)

Explanation: The original speed is multiplied by the ratio of larger tire diameter to original tire diameter to calculate the actual speed with larger tires.

3. Importance of Speed Calculation with Larger Tires

Details: Larger tires cover more ground per revolution, making your speedometer show slower than actual speed. This calculation helps maintain accurate speed awareness.

4. Using the Calculator

Tips: Enter the original speed in mph, original tire diameter in inches, and new larger tire diameter in inches. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why does speed change with larger tires?
A: Larger tires have greater circumference, so each revolution covers more distance, effectively increasing speed at the same RPM.

Q2: How do I find my tire diameter?
A: Check tire specifications or use a tire size calculator based on the numbers on your tire sidewall (e.g., 265/75R16).

Q3: Does this affect odometer readings?
A: Yes, larger tires will cause your odometer to underreport actual mileage by the same ratio.

Q4: How much does speed typically change?
A: A 10% increase in tire diameter results in about 10% higher actual speed than indicated.

Q5: Should I recalibrate my speedometer?
A: Yes, for significant tire size changes, speedometer recalibration is recommended for accurate readings.