This wheel nut (576103) was introduced to reduce tendancy of wheel rim damage, the idea was a larger diameter (1 1/16") would increase contact surface area. It worked. But the 9/16" diameter wheel stud was a new weaker link, this was then upgraded to a larger M16 wheel stud, the wheel nut remained 1 1/16" (27mm) AF with but with an M16 thread.