Car / SUV / Van / Light Truck Tire Calculator (P-metric)
SIX EASY STEPS! ( For calculation purposes P205/65R15, LT205/65-15 and 205/65R15 are the same. )
Manufacturer's Suggested Tire Size *

1 Select the tire Width in MM (Inches)

2 Select the Aspect Ratio (tire height/width)

3 Select the Rim Diameter in inches

CALCULATED:
Overall Wheel diameter in Inches
Wheel Circumference in Inches
Wheel revolutions per mile
Wheel revolutions per second @ 65MPH
ALTERNATE or Desired Tire Size *

4 Select new tire Width in MM (Inches)

5 Select new tire Aspect Ratio (tire height/width)

6 Select new Rim Diameter in inches

CALCULATED:
Overall Wheel diameter in Inches
Wheel Circumference in Inches
Wheel revolutions per mile
Wheel revolutions per second @ 65MPH
NOTE: Changing the tire diameter CHANGES the SPEEDOMETER accuracy!

This ALTERNATE tire size will cause the 'Actual Vehicle Speed' to be

mph, when the speedometer reads exactly 65mph.

Or, when the 'Actual Vehicle Speed' is 65mph the speedometer will now read

Also, the ground clearance of the vehicle will change by inches.


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* It is possible to specify non-existent tire sizes. The Manufacturer's suggested tire size may be found
in the manual or on the edge of the open driver's door. MM = millimeters metric system, 25.4 mm = 1 inch.

Web Page by Jim Shook 09/03/2003 Updated 03/13/2006
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