Cross Section: This is the width of the tire in millimeters from sidewall to sidewall.
Aspect Ratio: The aspect ratio is a ratio of the tire's height to the cross section width. Written as a percentage. For example and Aspect ratio of 40 equals 40%.
Rim Diameter: The rim diameter is in inches and indicates the size of the rim that the tire will be mounted on. This is the diameter of the opening where the tire is mounted on a wheel.
To figure a tire's overall height follow this formula
Overall wheel height is 24.72 inches
This will vary slightly by manufacture, inflation pressure, sidewall stiffness, etc.