IIRC, the centre of the Dunlop mags are not machined so you can't use them as a reference point when balancing or mounting the wheels. As mentioned above it would be fairly simp to have the centres machined up which would help a great deal with balancing the wheels. It is simple to centre the wheels when mounting them on the vehicle is you use two regular Triumph lug nuts to locate the wheel first and then secure the where with the original lug nuts on the two remaining studs.