[Rick Parker]

A few years ago this topic was heavily discussed. The (5) 1/2" threaded studs (I used 6) themselves are specified to be tightened to 80-85 ft lbs of torque when used in (Ford OEM applications). Tell that to the Monkeys with an impact wrench at the tire shops. My personal opinion after dealing with the possibility of this is that the "sleeve nuts" are not made of a hardened material as are normal OEM lug nuts. This often leads to galling of the tapered face as it is tightened. When this happens more torque is required to achieve the same clamping force and the sleeves deform or split. Verify that the angles on the nuts and the adapters are the same. It is also possible that the stud hole seats on the adapters are machined at 45 degrees and the nuts are 60 degrees, thus being mismatched (not good) and will cause the described problem.
Two things should be done to help eliminate this. As previously mentioned by "strictlypersonl", calculate what the installed length of the stud should be to achieve full thread engagement, leaving full depth for the internal hex wrench. Then and this is MY OWN OPINION use anti sieze on the threads and tapered mating face of the sleeve nut. I was then able to achieve the desired torque repeatedly without any damage to the nuts.