Understanding Car Wheel Hubs: Size, Width, PCD, Offset, and Center Hole

The wheel hub is a crucial part of your car that connects the wheel to the vehicle. Here's a breakdown of key hub measurements to consider:

Size (Diameter)

Often referred to as "hub size" (e.g., 15-inch hub).

Larger diameters on sedans can enhance visual appeal and improve handling, but may increase fuel consumption.

Width (J Value)

This value determines compatible tire choices.

Different J values for the same size tire will affect recommended tire width and aspect ratio.

PCD (Pitch Circle Diameter) & Holes

PCD refers to the diameter of a circle created by the center points of the wheel hub's bolt holes.

PCD is crucial for safety and should match your car's original PCD for proper fitment.

Common PCD notations include "4X103" (4 bolts, 103mm diameter) and "5X114.3" (5 bolts, 114.3mm diameter).

Offset (ET)

This is the distance between the hub mounting surface and its centerline.

A positive ET value indicates the hub surface sits closer inwards, while a negative value means it protrudes outwards.

Most passenger cars have positive ET values.

Center Hole

This hole in the hub center connects to the vehicle's axle.

Its diameter is crucial for proper wheel alignment.

While adapters can modify hole size, such modifications are risky and should be approached with caution.

Remember: Upgrading or modifying wheel hubs requires careful consideration of these measurements to ensure safety and proper vehicle performance.