I need the exact measurement of the hole in the middle of the rear wheel on a BX. The reasoning for this is that I have acquired a set of rear wheel spacers that are designed for the Jeep vehicles with a 71.5 mm hub. I want to machine a centric ring to fit over the Jeep hub on the adapter and to fit the hub of the Kubota rim. All of my instruments are too large to fit inside the rim to determine this measurement. thanks