1. What is Wheel Speed Correction?

Wheel speed correction calculates the actual vehicle speed when changing tire sizes. When you install larger or smaller tires than original equipment, your speedometer reading may become inaccurate.

2. How Does the Calculator Work?

The calculator uses the wheel speed conversion formula:

Where:

• \( Speed \) — Current speed reading (mph)
• \( New_{\text{size}} \) — Diameter of new tires (inches)
• \( Old_{\text{size}} \) — Diameter of original tires (inches)

Explanation: Larger tires rotate fewer times per mile than smaller tires, causing the speedometer to under-report actual speed if not corrected.

3. Importance of Speed Correction

Details: Accurate speed measurement is crucial for maintaining proper vehicle operation, fuel efficiency calculations, and avoiding speeding tickets due to incorrect speedometer readings.

4. Using the Calculator

Tips: Enter your current speed, original tire diameter, and new tire diameter. All values must be positive numbers. For best accuracy, measure actual tire diameter rather than relying on nominal size.

5. Frequently Asked Questions (FAQ)

Q1: How much does tire size affect speedometer accuracy?
A: A 10% increase in tire diameter will cause speedometer to read about 10% lower than actual speed.

Q2: Does this affect odometer readings too?
A: Yes, odometer readings will also be inaccurate by the same percentage as the speedometer.

Q3: What's the best way to measure actual tire diameter?
A: Measure from ground to top of tire (with proper inflation and vehicle weight on tires), then double that measurement.

Q4: Do wider tires affect this calculation?
A: Only if the overall diameter changes. Width alone doesn't affect speed calculation unless it changes the diameter.

Q5: How do I correct my speedometer after tire change?
A: Many modern vehicles can be reprogrammed. Some may require a mechanical speedometer gear change or aftermarket correction device.