good post thats why its always handy to have the torque wrench lieing aroundA short lesson on torque of bolts, particularly wheel lug bolts.
All nuts and bolts have a recommended tightening torque based on the size of the bold (10mm 12mm etc) and the thread pitch (1.0, 1.25, 1.5 etc)
The chart below shows typical wheel lug sizes etc.
I am posting this because I guarantee most of you have your wheel lugs far too tight. There are only a few rare mechanical problems caused by overtight nuts but a lot of physical ones.
Damaged wheels and mudguards when you stand on the wheel brace and it fly's off.
Divorce because the wife cant change the wheels because bolts are too tight. If they are correct a women can easily undo them.
As you can see from the chart a 12mm x 1.5 bolt (typical VW wheel bolt) has a tighten torque of 80 Foot pounds (108Nm)
We will deal in foot pounds because its easy for a human to associate.
Your average VW wheel brace is 1 foot long. So, if you placed 80 pounds of weight at the end of the brace the bolt would be tightened to its correct torque.
To put it another way. If you weigh 90 kilos (200 pounds) and you bounce your weight on the end of the wheel brace to tighten the bolt you have just over tightened it by over 200%. That is exactly why you can't undo them.
Now I am not suggesting anyone have their wheel bolts too loose but you can see an average person can easily over tighten them.
After rallying cars for years and always tightened wheel bolts/nuts to the specifications I have never had one come loose or fall off. And they are always easy to undo in a flash.