Left hand lug nuts are back, baby!
72,
You keep missing the point. Nobody in their right mind purposely leaves lug nuts loose. However, people get distracted, called away to answer the phone before fully tightening the nuts, have other things on their mind, whatever, & the nuts are not properly tightened. These incidents are what LH threads are for.
Wheels, both L & R side, have come off cars while being driven because the nuts were not tightened so it does happen.
As for the over torqued broken stud........
Obviously you know you have a problem...& you will be getting the bus home....
I haven't missed your point at all. If you "get distracted" there's about a hundred different things you can do that can kill you eventually. Should there be engineering controls to make sure you install all your cotter pins, or fasten your master cylinder cap, or grease your bearings, replace that drain plug, don't leave a wrench somewhere it can fall off of later, torque any number of things that spin at high rpm, etc, etc, etc. Or maybe you could learn to double or triple check things that are important. This is why aviation has check lists for important things.
If you leave lug nuts that loose it doesn't matter what direction your threads turn, you will eventually have problems. Up to and including your wheel shearing the studs off. Yes, if you have RH threads and leave your lug nuts loose on the left hand side they will loosen more, that is true. But if you left them so loose that they loosen further just because of the rotational direction of the wheel, you were going to have problems
ANYWAY. Somebody will say they lost a wheel on the driver's side because of it, and I'll happily tell them if they hadn't they'd eventually sheared the damn studs off the other side and lost a wheel anyway. The left side just happened faster. Either way you're going to have issues. There's a reason "finger tight" isn't the lug nut torque spec, and it has nothing to do with the direction of the threads.
Do you check the lug nuts on the passenger side of your vehicle after you back up? It's spinning the wheel opposite the tightening direction on the threads...
Chrysler was the last one to run LH lug nuts on production cars in the US, it's debated a bit but around 1970 they went away. It's literally been around 52 years now since this was done widely on production vehicles. Unless we all switch to a single center lug, I don't see it changing back, so you'd best learn to check your lug nuts.
There were LOTS of others that used left hand threads. Chrysler probably used it longer than anyone else, however. I think it is a holdover from the early Mopar days, when the wheels were held on with bolts, threaded into the drums, which were held on by tapers and nuts. (My 33 imperials, and my 49 plymouth).
It was a holdover from the
horse and carriage days. Somebody figured out that the central spindle nut on a wooden wheel would loosen unless the threads tightened in the primary direction of rotation. It was carried over to automobiles, but that made sense originally because of the spindle mounted wheels and knock off style spindle nuts. But once multi-lug wheel bolt patterns were adopted it was slowly abandoned, the lug nuts aren't on the axle. Not to mention that the materials had changed (no more wooden wheels!) and the torque spec on the fasteners had increased considerably. Making the whole thing moot, which was realized at different points in time by all the manufacturers. Chrysler was just the last to drop it, at least in the US. GM gave it up years and years before that.
