Ply rating:ATV tires come in different ply ratings: 2-ply rating, 4-ply rating, 6-ply rating, 8-ply rating, etc. The higher the ply rating, the stronger, but heavier the tire. For example: The most aggressive mud tires are built with higher ply ratings for ultimate strength.
ATV tires are commonly measured by Height x Width x Inner Wheel Diameter (HxWxID) in inches.
To determine the diameter of a wheel: Measure the width of the bead area of the wheel (not the outer rim). In the diagram above, the diameter measures 12 inches.
To determine the offset and width of a wheel: Measure from the center weld to the center of the tire bead area on both sides of the wheel. The outer measurement will be the one with the valve stem. The offset of a wheel is stated by reading the measurement of the inside first, then the measurement of the outside (valve stem side). For example: In the diagram above, the offset is 5+2; meaning the inside half of the wheel measured 5 inches, and the outside (valve stem side) measured 2 inches. Add these 2 numbers together to find the total width of the rim (7 inches).
Note: If the rim has a tire on it, usually the tire will have the rim diameter imprinted on it (8", 9", 10"...). You can also measure the rim from inside using the diagram above and getting the measurements as close as possible.