Left hand lug nuts are back, baby!
- Thread starter pishta
- Start date
-
72blu,
Post #20. Uh.....
The car needs nuts/bolts to hold the wheels on, the size will be the same for 4 wheels. How much extra do you think it will cost to make half of them RH thread & half of them LH? A few cents per car?
A loooooooooooooooooooooooooooooooot less than adding GPS/governor locks, breathaliser i'lock, distance sensors.
The point that you keep failing to get is that LH wheel studs was a safety device that had notionally zero cost. It has always surprised me that more companies did not adopt it. You seem to think nobody can make a mistake & not torque wheel nuts properly. Well they can & they have. A LH wheel that had has it's LH nuts tightened, say beyond finger tight, but not up to spec could quite well never come loose. Job done, LH threads. A LH wheel with RH threads with insufficiently tightened nuts will almost certainly come loose. And while astute drivers like the hobbyists that frequent forums like this might feel a wheel wobble or vibration of a loosening wheel, Grandma might not...
Post #20. Uh.....
The car needs nuts/bolts to hold the wheels on, the size will be the same for 4 wheels. How much extra do you think it will cost to make half of them RH thread & half of them LH? A few cents per car?
A loooooooooooooooooooooooooooooooot less than adding GPS/governor locks, breathaliser i'lock, distance sensors.
The point that you keep failing to get is that LH wheel studs was a safety device that had notionally zero cost. It has always surprised me that more companies did not adopt it. You seem to think nobody can make a mistake & not torque wheel nuts properly. Well they can & they have. A LH wheel that had has it's LH nuts tightened, say beyond finger tight, but not up to spec could quite well never come loose. Job done, LH threads. A LH wheel with RH threads with insufficiently tightened nuts will almost certainly come loose. And while astute drivers like the hobbyists that frequent forums like this might feel a wheel wobble or vibration of a loosening wheel, Grandma might not...
The rotational force exerted on a lug nut that's off the center axle is tiny. Tiny. If you tighten your lugs to even 50% of what they're supposed to be it would never be an issue. Do you think that the nuts on the RH threads on the right side of your car would tighten beyond finger tight? They won't. They might not unthread and fall off, but they're not going to magically tighten enough to solve any problems for you either.
And for every "grandma" that tortured their lug studs with finger tight lug nuts that wouldn't fall off but remained loose enough to cause issues later there's someone out there whose LH studs sheared off completely because the not-so-bright guy at the tire shop overtorqued the LH threads to the point of failure trying to loosen them. Heck some of those failures might even happen later on the road if they weren't completely twisted off to start with. There are plenty of pictures on this very forum about sheared off LH wheel studs.
They cause more problems than they solve. There are just as many people out there that can't grasp the concept of LH wheel studs as there are people that don't check their lug nut torques. They're probably the same people anyway, that's a ven diagram with a lot of overlap. And a few cents per car changes a lot of decisions at the manufacturing level. Pinto fuel tank bombs only cost a few cents per unit to solve, that went to production.
I just don't see the argument. The LH thread doesn't accomplish anything that a properly torqued lug nut doesn't already do. So unless you plan on leaving your lug nuts loose, there's no benefit at all. And there is a drawback, because somebody is gonna snap a few off at some point. And unless you're having the studs on your modern cars changed, you probably count everyday on the fact that with anything close to proper torque there's no issue.
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....
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....
33IMP
Well-Known Member
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).
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.
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.
I have a friend who road races at Summit Point, he is actually an instructor. Had a left front wheel come off the race car. Got distracted changing tires at the track, it cost a lot of money to fix the damage. I started changing tires part time in college and was instructed on Mopar left hand lugs, sure grips, and other knowledge to do a job right. LH lugs are sound engineering, but even Chrysler gave up after 1970? Stupid wins.
pishta
I know I'm right....
Boy, after setting this pot on boil, I realized that the bit of information I got (left hand thread) was actually split between 2 races. Both Xfinity and Cup series run new cars, but I heard the Xfinity cars still run 5 RH lugs and the cup series run the single LH/RH hub nut. So when I heard the lug nut comment (in the cup race) , I naturally assumed the old was new again until I was told the xfinity cars still run 5 lugs. Make sense? Am I wrong on the Xfinity cars having the old 5 lugs?
33IMP
Well-Known Member
Watching the tail end of today's xfinity race..... they still use five lugs.
pishta
I know I'm right....
Good enough for IMSA?
Note safety bail.
Note safety bail.
Dartswinger70
Well-Known Member
yeah the old Brit cars had knockoffs with a leather coated hammer in the trunk to literally "knock off" the spindle nut.
33IMP
Well-Known Member
Yep. And so did corvettes and cobras!
Funny thing is, the few minutes of research I did found that the vettes used right hand threads on the DRIVERS side , and left hand threads on the right side of the car. (Unless, of course, the source was full of ****....)
69_340_GTS
Well-Known Member
In NASCAR Cup, all 4 corners of the car have (single) left-hand threads on the hubs/nuts. There are 6 drive pins on the hub, and 18 drive pin holes in the wheels. The wheel can't spin, or come loose, if the pins are engaged and the nut is tight. But nobody seems to know why they are using left-hand threads on all 4 corners.
Probably because they actually did the math, the wheel guns are calibrated to provide exactly the right torque spec, and when properly torqued the psi on the nut will be more than enough to resist the small force exerted on the nut by the rotation of the wheel.
Correct, PLUS the bevel in the wheel and on the 5 individual lug nuts locks the nuts in place. If I am not mistaken, the single large nut they use in the center has a flat contact surface. So they need to be directional in order not to back off.
harrisonm
Well-Known Member
Dartsun
Mopar Dude
Left hand lug nuts suck
Yes, and it’s such a tiny force that it’s completely irrelevant if you just tighten the lug nuts. Which is why no major manufacturer that uses a multi-lug pattern uses LH threads on the left side of the car and haven’t for 50 years.
If you truly understood the physics at hand, you wouldn’t worry about it.
And, if you really understood the physics, you wouldn’t move a car under power with finger tight lug nuts regardless of which direction the threads go or which side of the car they’re on.
oi81b4uu812b4
Well-Known Member
Left hand lug nuts went extinct because they got broken off by unknowing people. And impact drivers at the tire shop did a majority busting them off.
Centerlock wheel nuts have to worry about pins being sheared off and the Centerlock nut loosening itself under braking on the right side.
Centerlock wheel nuts have to worry about pins being sheared off and the Centerlock nut loosening itself under braking on the right side.
Last edited:
It’s also true that the different metals used for brake drums, wheel studs, lug nuts and the actual wheel all have different thermal expansion rates, so that heat cycling from braking will loosen lug nuts. Wheel balance and harmonic vibrations will do the same.
Which is exactly why every car and wheel manufacturer will provide a mileage interval for checking your lug nut torque.
And if you’re actually checking your lug nuts periodically like you’re supposed to then it doesn’t matter which direction the threads go because the lug nuts will be tight!
Last edited:
Just a minor clarification to your first point-
"It’s also true that the different metals used for brake drums, wheel studs, lug nuts and the actual wheel all have different thermal expansion rates, so that heat cycling from braking will loosen lug nuts. Wheel balance and harmonic vibrations will do the same."
...if the rotational forces are against them.
Way too much engineering style t crossing and i dotting here for me now.
I've never had lugs loosen themselves for any of those reasons...ever.
...and I don't periodically check the torque...ever.
...but you win.
Congratulations.
harrisonm
Well-Known Member
@YY1, have you ever driven a car that you just hand tightened the LH thread lug nuts on?
I am not an engineer, but I took several physics classes in college. Lugs are torqued for a reason. I agree with @72bluNblu about torquing and checking lug nuts. And I agree with @oi81b4uu812b4 that the LH thread lug nuts probably went extinct because tire busters and mechanics kept breaking them. It happened to me at a tire shop once a long time ago.
I think you could probably talk until you are blue in the face, and I doubt that anybody on this forum is going to buy what you are trying to sell.
I am not an engineer, but I took several physics classes in college. Lugs are torqued for a reason. I agree with @72bluNblu about torquing and checking lug nuts. And I agree with @oi81b4uu812b4 that the LH thread lug nuts probably went extinct because tire busters and mechanics kept breaking them. It happened to me at a tire shop once a long time ago.
I think you could probably talk until you are blue in the face, and I doubt that anybody on this forum is going to buy what you are trying to sell.
No clarification needed, the rotational forces don't have to be against the direction of the threads for thermal expansion or harmonic vibrations to loosen the lug nuts. Those forces will loosen lug nuts regardless of the direction of thread and side of the car. Which is why EVERY wheel and vehicle manufacturer out there has a mileage schedule for re-torquing lug nuts. Because those forces can loosen even properly torqued lug nuts. Rotational force can not, they will only loosen lugs that are already not torqued to spec- and actually, they have to be VERY loose for that to happen. Now, once loosened by other forces will the rotational force continue to spin the loose lug nut off? Sure. But at that point the lug is already loose enough that damage will be done to the wheel and stud, regardless of the direction of rotation.
Bottom line, use proper torque and check it periodically and you'll never have an issue. If rotational force was such a problem, lawyers would have had a field day with manufacturers using only RH threads on every car made since ~1970. Remember what happened with the Ford Explorers and Firestone tires? And that was a pretty small number of accidents. Every moron that's ever had a wheel come off would be in on a class action lawsuit if there was anything to it beyond the complete negligence of the driver/mechanic that's tightening the lugs.
I agree, you don't understand all the forces at work well enough to have a relevant, informed opinion. Thinking finger tight lug nuts won't allow a wheel to wobble should have been my first clue that you've absolutely no idea what you're talking about. A finger tight lug nut will not produce the clamp force needed between the wheel and hub to resist the road forces acting on the wheel. This is basic.
How could you possibly know the first thing if you never do the second thing? I mean seriously, if you never check the lug nut torque then how could you possibly have the foggiest idea what's going on?
If you're too lazy to do something as important and easy as checking lug nut torque periodically, you've got no business driving a classic car.
...but you win.
Congratulations.
This isn't about winning, just the facts. A multi-lug wheel with properly torqued lug nuts won't have any issues because of the direction of wheel rotation.
-
