Offset is the distance between the hub mounting face at the back of the wheel and the wheel's centreline.

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']

The offset can be one of three types.

Zero Offset:

The hub mounting surface is even with the centerline of the wheel.

Positive:

The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.

Negative:

The hub mounting surface is toward the back or brake side of the wheels centerline. "Deep dish" wheels are typically a negative offset.

Standard pumas can have wheels with an offset between 35 and 38.

[edit]PCD
PCD stands for 'pitch circle diameter' and is the diameter of a circle drawn through the centre of your wheel's bolt holes. P.C.D. is measured in millimeters and also indicates the number of studs or bolts the wheel will have. Puma Alloy Wheels are usually 4x108 [i.e. 4 bolt holes drilled through the centre of an imaginary 108mm circle]




[edit]Centrebore
The 'centerbore' of an alloy wheel is the size of the hole at the back of the wheel which the 'hub' fits into. To help the wheels to seat properly this hole needs to be an exact match to the size of the hub.

Most modern wheels are what's called 'hub-centric' - this means that the hub which protrudes from your car [and mates with the equivalent sized hole at the back of your wheel] is 'load bearing'. All the studs or bolts do therefore is hold the wheel onto the hub!

If you have' lug-centric' wheels, the state of your studs or bolts is obviously more critical - be sure to replace these from time to time and always 3/4 tighten the wheels off the car to ensure they're centred.

The centrebore of most pumas is 63.3

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