what is wheels SIZE, ET,PCD and CB?

Wheels have different specifications that determine their size and compatibility with vehicles. Here are the meanings of the terms you mentioned:

Wheel Size: Wheel size refers to the diameter of the wheel, typically measured in inches. It is commonly expressed as a combination of numbers, such as "16 inches" or "18 inches," indicating the diameter of the wheel from one edge to the other.

Wheel ET (Offset): The wheel offset, often referred to as ET (Einpresstiefe in German), is a measurement that determines the positioning of the wheel mounting surface relative to the wheel's centerline. It is usually expressed in millimeters (mm). The offset can be positive, negative, or zero.

Positive Offset (ET): When the mounting surface is toward the outside (away from the vehicle's centerline), it is called a positive offset. This pushes the wheel further into the wheel well.

Negative Offset (ET): When the mounting surface is toward the inside (closer to the vehicle's centerline), it is referred to as a negative offset. This brings the wheel further out from the wheel well.

Zero Offset (ET): When the mounting surface is exactly at the centerline of the wheel, it is considered a zero offset.

Wheel PCD (Pitch Circle Diameter): PCD refers to the bolt pattern of the wheel, which indicates the number of bolt holes and the diameter of the imaginary circle they form. It is usually expressed in millimeters (mm) and given as a set of two numbers, such as "5x114.3" or "4x100".

For example, a PCD of "5x114.3" means there are five bolt holes, and the diameter of the circle passing through their center is 114.3 millimeters.

The first number represents the number of bolt holes or studs on the wheel.

The second number indicates the diameter of the imaginary circle passing through the center of the bolt holes.

Wheel CB (Center Bore): The wheel center bore, also known as hub bore or center hole diameter, refers to the opening at the center of the wheel that fits over the hub of the vehicle. The CB is measured in millimeters (mm) and is important for ensuring proper centering and fitment of the wheel onto the hub.

When a wheel is properly centered on the hub, the weight of the vehicle is evenly distributed, reducing the chances of vibration or other issues. The CB size must match or be larger than the hub diameter of the vehicle to ensure a proper fit.

For example, if a vehicle has a hub diameter of 67.1 mm, the wheel's CB should also be 67.1 mm or larger for a proper fit.

It's important to note that wheel size, ET, and PCD,CB are crucial factors in selecting wheels that are compatible with a specific vehicle, as they must match the requirements specified by the manufacturer.