Shafz,Car alloy wheel fitment etc, offset, PCD, and tyre size available at this link
The link below tells you effectivly how a tyre/wheel size will affect your speedo reading, thought it could be good for people before they buy wheels/tyres.
What is PCD?
PCD or Pitch Circle Diameter, to put it simply is the distance between holes diagonally. All of the MG Rover range (except the rover 75/MG ZT) share the same PCD
MG ZR PCD is 4x100mm
Centre Bore is 56.1
The MG ZR offset is 38..45, the offset of a wheel is the measurement the wheel is offset from the centre line of the overall width of the wheel. You cn go above this...alloy ill either stick out too much or too less
A wheel which sits further under the wheel arch with a small outer rim is normally a negative offset as per Diagram A below, and shown as 'ET' offset. A wheel which sits further out and has either a larger outer rim or a small outer rim and a large block which takes the hub mounting face beyond the centre line is normally a positive offset and shown as an 'ET' offset.
Hopefully this will help people so thought id post it up