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Valor MotorWorx Tools

Tire Size Calculator

Compare your current tire size to a new size. See changes in diameter, sidewall, revs per mile, and how much your speedometer reading will be off with the new setup.

Tire sizes
Current tire (stock / baseline)
Format: 275/60R20 → 275 width, 60 aspect, 20 rim.
New tire (what you’re considering)
We’ll assume the speedometer is calibrated to the current tire and show the actual speed on the new tire.
Results
Spec Current New Diff
Diameter
Diameter (mm)
Section width
Width (mm)
Sidewall height
Sidewall (mm)
Circumference
Circum. (mm)
Revs per mile
Speedo 60 mph → Actual — mph
Enter tire sizes and click calculate to see speedometer error.
For planning only. Real-world fitment still depends on wheel offset, ride height, alignment, and body clearance. Always verify clearance and follow your tuner’s and installer’s recommendations.