banner

What is the size,pcd,et and cb of wheel ?

January 13, 2025

When it comes to wheels , the terms: size,PCD,ET, and CB refer to important specifications that ensure proper fitment and performance on a vehicle. Here's a breakdown of each term:


1.Size of the Wheel

The size of a wheel typically refers to two key measurements:diameter and width.

Diameter: The overall diameter of the wheel, usually measured in inches. Common sizes include 15-inch, 16-inch, 17-inch, 18-inch, and so on. This measurement corresponds to the distance from one end of the wheel to the other, from edge to edge.

Car wheel size diameter and width diagram

 

Width: The width of the wheel is also measured in inches and refers to the distance between the inside edges of the wheel's rim, where the tire sits. For example, you might see a wheel labeled as 18x8.5, which means the wheel has an 18-inch diameter and an 8.5-inch width.

Car wheel width diagram

Example: A wheel size of 18x8.5 means:

· 18 inches in diameter

· 8.5 inches in width


2.PCD (Pitch Circle Diameter)

· Definition: PCD refers to thediameter of the circle formed by the centers of the wheel’s bolt holes.

· Format: It's represented by two numbers: the number of bolt holes (studs) and the diameter of the circle (in mm). For example,5x114.3 means:

o  5 bolt holes

o  114.3 mm diameter of the circle passing through the center of the bolt holes.

Example:5x114.3 means:

· 5 bolt holes

· A bolt circle diameter of 114.3 mm

Wheel PCD meaning and bolt pattern measurement diagram

3.ET (Offset)

· Definition: ET, or offset, is the distance from the wheel’s mounting face (the part that contacts the hub) to the wheel’s centerline.

· Types:

o Positive Offset (ET +): The mounting face is towards the front (towards the wheel's outer side), pushing the wheel inward.

o Negative Offset (ET -): The mounting face is towards the back, pushing the wheel outward.

o Zero Offset (ET 0): The mounting face is aligned with the centerline of the wheel.

Example:ET40 means:

· The mounting face is 40 mm towards the outside of the wheel centerline.

Car rim offset ET measurement diagram

 

 

4.CB (Center Bore)

Definition: The center bore is the diameter of the hole in the middle of the wheel, which fits over the hub of the vehicle. It’s crucial for the wheel to match the hub size to ensure the wheel is properly centered.

Common Sizes: Center bore sizes vary based on the vehicle make and model. For instance, common center bore sizes are 56.1 mm,66.1 mm, or 70.3 mm.

Example:CB 72.6 means:

· The center bore is 72.6 mm in diameter.


Wheel center bore CB measurement diagram

 

Planning to order custom forged wheels?

Size, PCD, offset (ET), and center bore (CB) are some of the key fitment specifications needed for wheel customization. If you are preparing an inquiry, see What Information Is Needed for a Custom Forged Wheel Quotation? to check what vehicle, fitment, design, and order information you should provide.

 

Have Any Questions?

You can contact us any way that is convenient for you. We are available 24/7 via !
Get the latest news and updates about our wheels by subscribing today.
Submit

leave a message

leave a message
For any request of information or technical support, fill in the form.All fields marked with an asterisk* are required.
Submit

home

products

Contact

Need Help? Chat with us

Start a Conversation

Hi! Click one of our members below to chat on