Tight Lug Nuts!

[Gadgeteer]

Okay... what’s going on here?

CW Grizz wrote....

The lugs on Fords, Chryslers, and many others had a left and right hand threads. The left hand threads were on the left side (driver's side) of the vehicle and the right hand were on the right side (passenger side) of the vehicle. The theory was that as the vehicle went forward the rotation of the wheels would keep the lug nuts or bolts tight.

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Then kbs2444 followed with...

I think I learned the "leftside is right hand, right side is left hand" rule on a 1957 Plymouth.

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These two theories, as stated above, are exactly the opposite.

As I recall, the hub nuts on my 1963 Healey 3000 with wire wheels and “knock-on” hubs were right hand threads on the left (driver’s) side and left hand threads on the right (passenger’s) side. (I just checked my factory repair manual and this is correct.)

I could be wrong, but, as I see it, any effect of rotational forces of the wheels would only apply to “hub” nuts, not wheel nuts. It just seems silly that the direction of rotation of a wheel would have any effect on whether or not wheel nuts stay tight.

I’d be happy to hear from a mechanical engineer on this subject.

Gadgeteer