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What does PCD mean?

The Pitch Circle Diameter (PCD) is the diameter of the circle which passes through the centre of all the studs, wheel bolts or wheel rim holes.

The easiest way calculate the PCD is as follows:

1) Measure the distance ‘S’ between two adjacent studs from the centre of each hole.
2) Calculate from the formula below

**Note: on 4 lug fitments you can measure from the center of one stud to the center of the stud directly opposite.

PCD Calculation Formula

4 Stud PCD = S / 0.7071

5 Stud PCD = S / 0.5878

6 Stud PCD = S / 0.5

–Courtesy of YHI

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What does Offset mean?

Offset is the distance between the hub mounting face at the back of the wheel and the wheel’s center line.

Offset is usually stamped or engraved into the wheel and is measured in millimetres of ‘ET’ [ET is the short form of the German word ‘Einpresstiefe’ which literally translates as ‘insertion depth’]

Positive Offset wheels have their mounting face toward the front face of the wheel. Most front wheel drive vehicles have positive ET wheels.

Zero Offset wheels have their mounting face even with the center line of the wheel and are by definition “ET 0″.

Negative Offset wheels have their mounting face toward the rear of the wheel – powerful rear-wheel drive cars often have wheels with negative offset.

–Courtesy of YHI