Sometimes if there is too much paint on the mating face of the flange (or a lump/paint drop) you tighten the wheel correctly, then through use the paint crumbles and falls out meaning that the wheel is now loose.
The same thing can happen when you fit the spare on a bakkie if there is dirt or mud on the mating face because it hangs under the chassis.
The mating face of a wheel should always be masked off when painted, and receive at most one coat of primer.'
EDIT: remember that wheels are actually held in place by friction between the two mating faces. so you don't want anything like paint getting involved here.
I had a wheel come loose at speed, but luckily I could slow down and stop safely using very light handbrake, car in neutral and slowly steering off to the side of the road. 3 bolts were missing when I finally came to a stop, but the wheel was still attached. I used one bolt from each of the rear wheels, and went to the nearest dealer and bought a new set of 20 bolts that cost me probably a thousand or so, at R45 per bolt. This is because the two remaining bolts on my wheels were damaged. Luckily the hub threads were fine.
What comes to mind about wheels:
1. Always tighten the wheels with the car jacked up.
2. Always torque in the correct sequence.
3. Always torque to the correct settings. Alloy wheels need only 100Nm applied. As stated by a wheel fitment expert: "The reason why tire spanners in your car's toolkit is so small is to prevent over torqueing the wheels. Tighten using only your hands and body weight. never use your feet."
I usually apply a dab of light grease or even engine oil to the threads of the wheel bolts when I fit them, and they usually go in and come out quite easily with no drama at all.
According to the experts, more damage is done by over torqueing than by under torqueing.
I was scared for months after this incident but luckily the fear wore off :biglaugh:
Can you post a picture of the damage to the hub threads? The alternative is to tap new holes between each existing hole in the hub, but since removing and refitting the hub is such an issue, you might as well replace it.