How to read the tire size "215/40R18" and how to calculate the outer diameter?

The tire outer diameter calculation results below are calculated based on the tire standard and may differ from the actual values. We use a different formula from the usual formula so that it will be close to the real value, but an error may occur depending on the manufacturer, rim width, rim diameter, etc. In particular, the error is large when the tire width is displayed in inches. The results shown here are approximate calculated values ​​and should be considered for reference only. In addition, we are not responsible for any disadvantage caused by the following calculation results. Please check directly with the retailer for accurate numbers.

Tire size display 215/40R18
Rim diameter (wheel diameter) 18 inches
Tire Width 215 mm
Flatness 30%
Tire outer diameter 629 mm
Tire size "215/40R18" rim change compatible tire size list
This list is a list that displays tires with tire widths and outer diameters that approximate the tire size of 215/40R18 . The tire width is displayed in the range of -50mm to +50mm, and the outer diameter is displayed in the range of -30mm to +30mm.

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