Tire & Wheel Size Calculator

Compare tire sizes like 205/55 R16 and 225/45 R17: wheel diameter, circumference, ground clearance change, and speedometer error.

🛞 Size 1

Format: 205/55 R16 → width 205, aspect 55, rim 16.
Enter values and click “Calculate”.

How does the tire & wheel size calculator work?

The calculator estimates the overall wheel diameter using: rim diameter + 2×tire sidewall height. Based on that, it calculates circumference, ground clearance change, and speedometer error.

This helps you understand whether an alternative size is reasonable and how it may affect handling, ride height, and speed readings.

What does the result show?

You’ll see diameter difference in percent, ground clearance change in millimeters, and the real speed when your speedometer shows 100 km/h.

FAQ

What diameter difference is acceptable?

A common recommendation is to stay within ±2% to avoid issues with ABS/ESP and ground clearance.

Why does the speedometer reading change?

The speedometer depends on wheel circumference. If the circumference is larger, your real speed will be higher than the indicated speed.