With the TST TPMS, the monitor would not recognize that the sensor was gone right away. I think there is a 30 minute period with no signal before the monitor reponds. And the studs shearing off was my own fault. I mounted the wheels after I had the new tires installed. I used a torque wrench that we have used before and didn't let it hammer away. I told myself at the time that I should be torquing them instead, but let it go. while replacing the lost wheel, I checked the other studs and all were close to the recommended torque. Lesson learned. ..
...We are at ST George for two weeks of serious rock crawling with friends and will find 24 more studs to replace the others so I can drive more relaxed. A very dumb move on my part, but it worked out ok.
The puzzling part was that we had come 800 miles before they snapped off.