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Replacement Wheels on a 2003 C4

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Since you're trying to replace the standard wheels with lesser offsets, you may have an issue with clearance for the brake calipers. I can't say for sure since I don't know what the actual clearances are for the standard offsets. If this is actually the case, you can always add spacers to make up for the lack of offset.

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Decreasing the offset (ET) moves the wheel further out as the offset value is the distance between the vertical rim centre line measured inwards from the hub mounting face.


As an example your current front is 8.0" with a 52mm offset. 


Moving to an 8.5" wide rim  will push the outer surface of the wheel outwards by 6.25mm (half the wheel width increase).  Further decreasing the offset to 45mm will add a further (52 - 45) = 7mm to this position pushing the wheel further out again. The final result would be a tyre which has its outer surface:

(7 + 6.25) = 13.25mm further out than your present wheel.


The calculation for the back wheel would be:  6.25+(65-55) = 16.25mm further out.


On my 2003 996 C2 the back wheels are 18 X 10" with a 65mm offset (Stock wheels) with 285 tyres and the tyres are close to the wheel arch opening.  I did have wheels on with a 55mm offset (fitted by previous owner) and the tyre wall was too far out.   


Hope this helps





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