# lug bolts vs lug nuts



## __TD__ (Mar 20, 2002)

All BMW tool kits in the boot have a tool for locating the wheel onto the rotor prior to inserting the bolts.

Alan, modulus of elasticity is a given materials ability to return to a previous dimension after being stressed. To use an example: a ladies thong panty. Stretch it slightly and it rebounds to it's former shape. Stretch it so it no longer returns to it's original dimension and you've exceeded it's modulous of elasticity. 

 razzmatazz


----------



## Weaselboy (Jul 7, 2002)

Razzmatazz said:


> *Alan, modulus of elasticity is a given materials ability to return to a previous dimension after being stressed. To use an example: a ladies thong panty. Stretch it slightly and it rebounds to it's former shape. Stretch it so it no longer returns to it's original dimension and you've exceeded it's modulous of elasticity.
> 
> razzmatazz *


I knew what it was... it just struck me as funny 

I do like your example though!


----------



## ruteger (Dec 31, 2001)

*No engineering reason*

I suspect that the true answer lies more in simple economics than any engineering or physics principle.

Using lug bolts is probably a cheaper, simpler route for manufacturing (the hub need only be drilled and tapped), whereas using lug nuts would be more labor intensive in that they require the hub be drilled, then a separate stud be press-fit inserted.

Domestic manufacturers would probably have _liked_ to use lug bolts, but because domestic passenger vehicles have historically required much larger, heavier wheel/tire combinations, they went with the lug nut/stud combination because, as previously mentioned, it's not exactly a piece of cake lifting and holding a heavy wheel/tire onto a hub while trying to insert a lug bolt, particularly at an inopportune moment on the side of a busy highway.

European cars, OTOH, have historically been much smaller than US vehicles, and used correspondingly smaller, lighter wheel/tire combinations. The Euro manufacturers went with the cheaper lug bolt system simply because they could get away with it.

Now that domestic and European vehicles are much closer in size, I'm sure that the reason for the difference today is nothing more than it would be too expensive for the domestic manufacturers to switch to lug bolts, not to mention that Americans are too used to the easier mounting that lug nuts afford.

It would be interesting to see what type of wheel fastening system much heavier European vehicles (like trucks) use. Although, they probably use lug bolts, too, simply because it would be too expensive to manufacture two different types of wheel mounting systems.


----------



## ruteger (Dec 31, 2001)

*Knock-offs*

Remember, too, that the old knock-off system used a large, threaded post with a single, large winged nut that was spun on or off by pounding on the wings of the nut with a large, lead mallet.

Imagine how much fun it would be if BMW and the other European manufacturers used *that* system to attach their wheels to their cars...


----------



## StevzZ3 (Apr 30, 2002)

*Lug Nut*

How is this: The lug bolt /nut . High speed wobble induced by overtightening lug nuts warping rotor or brake drum. Wheels are not hubcentric. Nothing to do with price.


----------

