Take a wheel off the car lay it face down on the grass/carpet etc.
Now place a steel rule across the hub face area inside the wheel, use another ruler/vernier to measure along length of ruler to see if it is closer than 60mm at ANY point between wheel spokes inside and the steel rule, AFTER you have added the depth of the disc to the figure, ie how far back the disc face is from the hub face/depth.
tabetha