How to use: Calculate tire dimensions and rolling characteristics from tire size code. Enter Width (tire width in mm, e.g., 225), Aspect Ratio (sidewall height as % of width, e.g., 60 means sidewall = 60% of 225mm), and Rim Diameter (wheel size in inches, e.g., 16). Format example: 225/60R16. Results show: Overall Diameter (total tire height), Circumference (distance per revolution), Sidewall Height (mm), and Revolutions per Mile. Used for: speedometer accuracy when changing tire sizes (±3% diameter = accurate speedo), fitment verification (clearance in wheel wells), performance impact (larger diameter = higher top speed, smaller = better acceleration), and odometer calibration. Standard sizes maintain vehicle handling and safety specifications.