Tire Size Calculator
Compare two tire sizes and see the difference in diameter and speedometer accuracy.
Diameter Difference
2.98% (24.97in vs 25.72in)
Formula
Diameter = Rim + 2 × (Width × Aspect Ratio ÷ 100 ÷ 25.4). A larger diameter makes your speedometer read slower than actual speed.
Frequently Asked Questions
What is the diameter difference for 225/45R17 vs 245/40R18?
2.98% (24.97in vs 25.72in).