Miata Tire CalculatorTire Calculator


Miata tire calculator Calculate speedometer reading after you change the size of your tires.

Original tire size: / R  
New tire size: / R
  Original tyre New tyre
185/65 R14 205/50 R15
Radius, mm    
Circumference, mm    
Circumference difference, mm  
Circumference difference, %  
Vehicle speed as speedometer reading is:*  
50 km/h 50  
80 km/h 80  
100 km/h 100  
120 km/h 120  
* Note: it is assumed that speedometer shows real speed with original tires.

Find more about Miata tire size calculator.