I bought larger wheels and tires for my 4WD Vanagon (the Tristar). Spacers were required for them to fit. I bought a set of 4 spacers, each with studs attached. So I first install the spacer using the original studs, then bolt the wheel onto the spacer with the new studs that are attached to the spacers. You get the idea.
The new studs that are attached to the spacer keep breaking. I have broken 9 so far. Fortunately, the wheel has not fallen off while driving. But I have driven home only to discover just 2 of 5 studs remaining on the wheel.
That's when I put the old tires on without the spacers and get new studs installed.
Here's the thing. They always break on the same wheel: the left-front (driver side). The brake disc appears to be true, the spacer has been measured and is true, and the wheel appears to be true.
If they broke on different wheels, I would just attribute it to weak metal. But it's always the same wheel.
Note that the car is 4WD with a viscous coupler, meaning there is always some power to the front wheels.
Any ideas on what's going on? Also, can anyone recommend a clever machinist/tire guy in the SF Bay Area who might be able to solve this puzzler?