The mm was a mistake I meant to put F and FR for the size 17’s to avoid confusion, have corrected it.
Both your Murcielago and Modena use 18F’s and 19R’s. Not sure exactly what the numbers are suppose to represents it appears to be something like diameter + 4 millimeters (+3 if you measure the lip), but yes the diameters are definitely different. If you look at the photos of your 18F front wheels and 19R rear wheels compared to photos of the 18F and 20R’s on an Enzo, Mazda, or Porsche 962 you can clearly see that the 20R’s are taller.
18F’s are:
13mm tall, 12 inside the lip.
4.5mm wide, 4mm inside the lip.
Your 19R’s should be:
14mm tall, 13 inside the lip.
6mm wide, 5.5 inside the lip.
20R’s are:
15mm tall, 14 inside the lip
6mm wide, 5.5 inside the lip
17FR’s will be:
12mm tall, 11 inside the lip
edit: 4mm wide, 3.5 inside the lip
