You'll need to know the diameter (
in inches) and width (also
in inches, often written with a J - so 4J x 14 would be a 4» x 14» wheel), the PCD (pitch circle diameter, or bolt pattern), which is stated as NxM, where N is the number of bolts and M is the diameter
in mm of a circle going through them all, e.g. 4x100, the
centre bore (the size of the
hole in...