Identify Your Wheels

The wheel rim is measured across the shoulder

Select the rim diameter to identify your wheel.  It may be written on the tyre
ie/     4.80/4.00 - 8  = 8 inch rim, 480mm tyre width
       145 R10   = 10 inch rim 145mm tyre width

The pcd is measured from the centre of 1 stud hole to the centre of the opposite stud hole