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RE: Self-Tightening Lug Nuts
Chris Pawlowicz wrote:
> I often have my lug nuts tighten up by themselves so that I need a
> 2 foot cheater bar on my socket wrench to unfreeze them. I *know*
> I torque them correctly to ~85ft/lbs with a torque wrench,
> immediately after they are easy to remove, but a month or two
> after and UGH!
> Don't know why they freeze by themselves but they do.
Chris,
You don't say where you're located, but I'd have to deduce that you live
somewhere in the northern hemisphere.
People used to attribute this tightening to rusting of the lug nuts to the steel
wheels. However, it's only since mag wheels have become commonly used that
automotive engineers have realized the phenomenon can no longer be explained
by rusted lug nuts, and have discovered the real reason.
The spontaneous tightening is caused by the Coriolis Effect. It is well
known that the Coriolis Effect is responsible for the clockwise rotation of
ocean currents (and bathtub-drain vortices) in the northern hemisphere, and
counterclockwise rotation in the southern hemisphere. I'm sure our
southern-hemisphere digest members will confirm that all BMWs delivered to these
areas are equipped with left-hand-threaded studs/nuts to preclude spontaneous
_loosening_ of their lug nuts.
Sorry.... I couldn't resist. ;-)
Regards,
Jerry
Arlington, TX (18-Jul-96, 19:37)
'95 540i-6 spd