GALLERY OF BROKEN STUDS
The following gallery is just a small portion of broken thread-in studs that have been shared with us. There are many more that most people don't bother documenting or sharing. Contrary to popular belief, the vast majority of these failures are not correlated to having wheel spacers. In fact, more than 50% of the failures shared with us occurred WITHOUT them. And, some of these failures were with brand new studs installed prior to the event.
Also, notice how almost all these failures occur inside the threads of the wheel hub, or flush with the hub face. This is a stress concentrated area and where the fundamental difference between a press-in style stud and thread-in lies. Press-in studs have much more material and no stress concentrations (thread starts/stops) at this point due to how it interfaces with the hub vs thread-in studs. Let the pictures and video do the talking.
Also, learn how coatings can cause potential wheel stud failure here