What Does the ET Value of a Tire Mean?

[MacAnthony]

Tire ET value refers to the Offset value, which is the deviation between the mounting surface of the wheel hub and the centerline of the rim, measured in millimeters. It can be positive, zero, or negative. A positive Offset value means the mounting surface is towards the outer side of the wheel, while a negative value means it is towards the inner side of the rim. Changing the ET value of the rim alters the track width of the vehicle, which is the distance between the centerlines of the tires. Simply increasing the size of the rim and tire without changing the ET value does not affect the track width. Using a rim with a smaller positive ET value will widen the track width, thereby reducing the shift in the vehicle's center of gravity during cornering and improving the cornering speed limit.