On the sidewall of a tire for a heavy vehicle the marking 385/65 R22.5 appears. What does the number 22.5 indicate?

Question

DentroTest · Accepted Answer

In the standardized tire nomenclature, the figure that appears after the letter indicating the internal structure (here the “R” for radial) indicates the inner diameter of the tire measured in inches (22.5"), which is the diameter of the rim on which it must be mounted. The nominal width is not measured in inches: it is given at the beginning of the marking and expressed in millimeters (385 mm). And inflation pressure is not part of this dimensional code, so it cannot be that number.

On the sidewall of a tire for a heavy vehicle the marking 385/65 R22.5 appears. What does the number 22.5 indicate?

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