Tire Size Comparison
Compare two tire sizes side by side. Enter both sizes to see diameter difference, speedometer error, and circumference comparison.
How It Works
Each tire diameter is calculated using the formula:
Diameter = (2 × width × aspectRatio / 2540) + rimDiameter
Speedometer error = (newDiameter / oldDiameter − 1) × 100%. A positive error means your speedometer reads lower than actual speed.
Frequently Asked Questions
How much can tire size differ before it causes problems?
Most manufacturers recommend keeping overall diameter within 3% of the original. Beyond that, speedometer error, ABS calibration, and clearance issues can arise.
How is speedometer error calculated from tire size?
Speedometer error = (newDiameter / oldDiameter - 1) × 100%. A larger tire makes the speedometer read lower than actual speed.