To determine tire size, separate the size by 25.4 to transform it from inches to millimeters

https://www.scribd.com/document/760939723/Unlocking-the-Puzzle-of-Tire-Dimensions-The-Relevance-of-a-Tire-Dimension-Calculator-173983

To determine tire dimension, divide the diameter by 25.4 to convert it from inches to millimeters