anybody know the scientific reason why lug nuts need to be rechecked?
12-09-19, 09:42 AM
#1
Lexus Fanatic
Thread Starter
anybody know the scientific reason why lug nuts need to be rechecked?
btw a buddy long ago said expansion of metals i.e. thermal expansion coefficients....
I finally put my snows on yesterday. They are on separate rims with another set of lug nuts.
Went downstairs in the garage at work, and all 20 were loose lol
Now we have 4 cars and 3 have snows, and honestly? I've never been able to put rhyme/reason on under what circumstances retightening is needed. More often, it is not. 2 of our cars are RWD so that means the front wheels cannot be torqued off the ground. But on the LS I said all 20--so off the ground doesn't seem to matter. The rears were tightened off the ground.
I grabbed this link and it really doesn't say why, rather that it's needed...
https://www.continental-tires.com/ca...orquing-wheels
I finally put my snows on yesterday. They are on separate rims with another set of lug nuts.
Went downstairs in the garage at work, and all 20 were loose lol
Now we have 4 cars and 3 have snows, and honestly? I've never been able to put rhyme/reason on under what circumstances retightening is needed. More often, it is not. 2 of our cars are RWD so that means the front wheels cannot be torqued off the ground. But on the LS I said all 20--so off the ground doesn't seem to matter. The rears were tightened off the ground.
I grabbed this link and it really doesn't say why, rather that it's needed...
https://www.continental-tires.com/ca...orquing-wheels
12-09-19, 10:44 AM
#2
From your link:
Torque is the unit of measurement for the twisting force that’s applied to a lug nut. Mechanics will ensure that each lug nut has been torqued to the vehicle manufacturer’s specifications when first fitting a wheel. But a second follow-up check is also necessary.
This is because, after a reasonable amount of time, the lug nuts will undergo the typical stresses and forces of a car in daily use. These stresses include supporting the weight of the vehicle, the rotational effects of driving, cycles of warming and cooling, and nudges from bumps in the road. Such stresses can cause a slight shift in the seating of the lug nuts, which may result in tightening or loosening.
The presence of dirt, sand, rust, or grit between surfaces such as the threads of the nut or between a nut and the wheel can also create “false torques” during the initial fitting, where the force applied overcomes the friction but doesn’t translate into clamping force.
For these reasons, many car garages and tire dealers will invite drivers to come back the next working day to have their wheels retorqued. It’s a quick procedure, usually offered free of charge, which involves inspecting each lug nut on the wheel to check if they are too tight or too loose.
If the lug nuts are too tight, they can cause severe problems such as stripping the fastener threads or stretching the wheel studs. They could also warp the brake drums, rotors, or hubs. With loose nuts, meanwhile, there’s a small risk that the wheel could come off while you’re on the road. The chances of this ever happening are very low – but if it did happen, your safety and that of other road users would be at risk.
Torque is the unit of measurement for the twisting force that’s applied to a lug nut. Mechanics will ensure that each lug nut has been torqued to the vehicle manufacturer’s specifications when first fitting a wheel. But a second follow-up check is also necessary.
This is because, after a reasonable amount of time, the lug nuts will undergo the typical stresses and forces of a car in daily use. These stresses include supporting the weight of the vehicle, the rotational effects of driving, cycles of warming and cooling, and nudges from bumps in the road. Such stresses can cause a slight shift in the seating of the lug nuts, which may result in tightening or loosening.
The presence of dirt, sand, rust, or grit between surfaces such as the threads of the nut or between a nut and the wheel can also create “false torques” during the initial fitting, where the force applied overcomes the friction but doesn’t translate into clamping force.
For these reasons, many car garages and tire dealers will invite drivers to come back the next working day to have their wheels retorqued. It’s a quick procedure, usually offered free of charge, which involves inspecting each lug nut on the wheel to check if they are too tight or too loose.
If the lug nuts are too tight, they can cause severe problems such as stripping the fastener threads or stretching the wheel studs. They could also warp the brake drums, rotors, or hubs. With loose nuts, meanwhile, there’s a small risk that the wheel could come off while you’re on the road. The chances of this ever happening are very low – but if it did happen, your safety and that of other road users would be at risk.
12-09-19, 10:45 AM
#3
Nothing scientific about it. If the tech at the shop doesn't torque the lug nuts properly they have time to catch it and re-torque them before your wheel flies off. Even if the proper torque is applied, little things like dirty threads or other contamination can give invalid torque readings resulting in under-tightened lug nuts. After you drive a bit, they will loosen further. Again, the re-torque interval is just to make sure nothing like that happened.
If there was really a scientific reason for you to re-torque your lug nuts after a certain amount of time/distance, then you'd have to do it every time you cross that threshold, not just once
If there was really a scientific reason for you to re-torque your lug nuts after a certain amount of time/distance, then you'd have to do it every time you cross that threshold, not just once
12-09-19, 12:06 PM
#4
Lexus Fanatic
Thread Starter
This is fact, on some rims/lugs, such as my LS430 winter tires. But not the others, for the most part. So could be a mine is not to reason why deal lol
In the real world, I torqued my rims to 76 ft. lbs. Drove 13 miles, and all 20 were loose. So it's prudent to check, yes. Then again on the factory rims/nuts, same car, they are not loose after remounting. Maybe I'm on to something! The nuts were provided by the outfit who sold the rims, not really anything special. MSW 17x8's forget what model, the one everybody gets.
In the real world, I torqued my rims to 76 ft. lbs. Drove 13 miles, and all 20 were loose. So it's prudent to check, yes. Then again on the factory rims/nuts, same car, they are not loose after remounting. Maybe I'm on to something! The nuts were provided by the outfit who sold the rims, not really anything special. MSW 17x8's forget what model, the one everybody gets.
12-09-19, 01:58 PM
#5
This is fact, on some rims/lugs, such as my LS430 winter tires. But not the others, for the most part. So could be a mine is not to reason why deal lol
In the real world, I torqued my rims to 76 ft. lbs. Drove 13 miles, and all 20 were loose. So it's prudent to check, yes. Then again on the factory rims/nuts, same car, they are not loose after remounting. Maybe I'm on to something! The nuts were provided by the outfit who sold the rims, not really anything special. MSW 17x8's forget what model, the one everybody gets.
In the real world, I torqued my rims to 76 ft. lbs. Drove 13 miles, and all 20 were loose. So it's prudent to check, yes. Then again on the factory rims/nuts, same car, they are not loose after remounting. Maybe I'm on to something! The nuts were provided by the outfit who sold the rims, not really anything special. MSW 17x8's forget what model, the one everybody gets.
12-09-19, 04:06 PM
#6
This is fact, on some rims/lugs, such as my LS430 winter tires. But not the others, for the most part. So could be a mine is not to reason why deal lol
In the real world, I torqued my rims to 76 ft. lbs. Drove 13 miles, and all 20 were loose. So it's prudent to check, yes. Then again on the factory rims/nuts, same car, they are not loose after remounting. Maybe I'm on to something! The nuts were provided by the outfit who sold the rims, not really anything special. MSW 17x8's forget what model, the one everybody gets.
In the real world, I torqued my rims to 76 ft. lbs. Drove 13 miles, and all 20 were loose. So it's prudent to check, yes. Then again on the factory rims/nuts, same car, they are not loose after remounting. Maybe I'm on to something! The nuts were provided by the outfit who sold the rims, not really anything special. MSW 17x8's forget what model, the one everybody gets.
12-10-19, 05:06 AM
#7
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12-10-19, 05:39 AM
#8
Lexus Fanatic
Thread Starter
My snows are on the MSW aftermarket rims, and with the rims came new lug nuts.
After driving 13 miles home yesterday, despite the rain, I decided to recheck, and lo and behold, more nuts were loose, but not all 20. It will be interesting to see at lunch if we are done or not.
I've been using a torque wrench for over 20 years, and I guess I just never gave it this much thought--I always carried it in my trunk until I didn't need to tighten anymore, sometimes 3X.
The answer here seems to be just like the case where my wife's coolant was high, after cooling overnight. Google had no explanation until I discovered the collapsed upper rad hose. It's surprising how some of the threads online say it's just a CYA--it isn't!
Again, before, I had thought there were two factors. Aftermarket rims, and tightening off the ground, such as the fronts on a RWD. Because with the BMW, they too need retightening with the snows on aftermarket rims, but the nuts are the factory ones (I don't know how they decide but with German cars usually the factory nuts which are actually studs as the hubs are female, are used), More to come...
After driving 13 miles home yesterday, despite the rain, I decided to recheck, and lo and behold, more nuts were loose, but not all 20. It will be interesting to see at lunch if we are done or not.
I've been using a torque wrench for over 20 years, and I guess I just never gave it this much thought--I always carried it in my trunk until I didn't need to tighten anymore, sometimes 3X.
The answer here seems to be just like the case where my wife's coolant was high, after cooling overnight. Google had no explanation until I discovered the collapsed upper rad hose. It's surprising how some of the threads online say it's just a CYA--it isn't!
Again, before, I had thought there were two factors. Aftermarket rims, and tightening off the ground, such as the fronts on a RWD. Because with the BMW, they too need retightening with the snows on aftermarket rims, but the nuts are the factory ones (I don't know how they decide but with German cars usually the factory nuts which are actually studs as the hubs are female, are used), More to come...
12-10-19, 06:35 AM
#9
Instructor
https://www.moderntiredealer.com/art...erious-subject
In the Modern Tire Dealer article it reads that lug nuts not tight enough will eventually loosen (may it be factors, others have mentioned in this thread, causing false torque readings...?)
In the Modern Tire Dealer article it reads that lug nuts not tight enough will eventually loosen (may it be factors, others have mentioned in this thread, causing false torque readings...?)
12-10-19, 07:04 AM
#10
Lexus Fanatic
Thread Starter
https://www.moderntiredealer.com/art...erious-subject
In the Modern Tire Dealer article it reads that lug nuts not tight enough will eventually loosen (may it be factors, others have mentioned in this thread, causing false torque readings...?)
In the Modern Tire Dealer article it reads that lug nuts not tight enough will eventually loosen (may it be factors, others have mentioned in this thread, causing false torque readings...?)
p.s. good article esp. the seat, and torque sections. Seat is probably how the etailer selling the rims decides whether or not to include new lug nuts/bolts...
12-10-19, 09:35 AM
#11
Lexus Fanatic
Thread Starter
went to the garage, and on the right side, no nuts were loose. On the driver side, about 4 were loose. dag--I think when I go 13 miles home, they will all be tight, and I take the torque wrench out of the car. So as you can see, if these were mounted by a shop, coming back the next day one time, won't cut it.
edit fyi this is the wheel it is a very popular one for snows due to low cost, and having an offset that is suitable, but also wider than stock. My wife said are these tires tiny? I said yes, I like my snows like my fiancés, tall, and slender
Last edited by Johnhav430; 12-10-19 at 09:40 AM.
12-10-19, 09:46 AM
#12
Instructor
went to the garage, and on the right side, no nuts were loose. On the driver side, about 4 were loose. dag--I think when I go 13 miles home, they will all be tight, and I take the torque wrench out of the car. So as you can see, if these were mounted by a shop, coming back the next day one time, won't cut it.
edit fyi this is the wheel it is a very popular one for snows due to low cost, and having an offset that is suitable, but also wider than stock. My wife said are these tires tiny? I said yes, I like my snows like my fiancés, tall, and slender
edit fyi this is the wheel it is a very popular one for snows due to low cost, and having an offset that is suitable, but also wider than stock. My wife said are these tires tiny? I said yes, I like my snows like my fiancés, tall, and slender
12-10-19, 09:53 AM
#13
Lexus Fanatic
Thread Starter
BMW with factory rims (style 189) and factory nuts which are actually male, they need to be retightened....
1998 Nissan factory rims no snows, need to be retightened
wife's 2011 GM SUV factory rims and nuts, never needs to be retightened
Maybe it all has to do with seating....
12-11-19, 08:23 AM
#15
Lexus Fanatic
Thread Starter
Man went home and loose again. I looked online and there were more references to the clamping force between nut and rim. So I took all 20 off and inspected. The nut is conical (factory is much less so)--it has to press against the holes in the rim. There is corrosion on all the nuts.
Anyway, I torqued to 76 ft. lbs. Drove to gym, 2 miles. Tight. Drove to home for shower. Tight. Drove to work. Loose again.
In thinking about it, I do not believe the nuts are rotating counter-clockwise, rather, the amount of clamping has changed. One problem noted online was room temperature nuts, applied in cold weather (bingo it was 25F when I did it and nuts were inside).
I can't believe how I am way overthinking, but such is life. For whatever reasons, no matter how much we think we know, we learn something new. The fact that I could drive 2 miles, then 2 miles, and all tight, makes me feel like nuts are not simply rotating counter-clockwise and off. It's a change between the rim holes and the nuts....I think they will get tightened, but I wanted to start over...
Anyway, I torqued to 76 ft. lbs. Drove to gym, 2 miles. Tight. Drove to home for shower. Tight. Drove to work. Loose again.
In thinking about it, I do not believe the nuts are rotating counter-clockwise, rather, the amount of clamping has changed. One problem noted online was room temperature nuts, applied in cold weather (bingo it was 25F when I did it and nuts were inside).
I can't believe how I am way overthinking, but such is life. For whatever reasons, no matter how much we think we know, we learn something new. The fact that I could drive 2 miles, then 2 miles, and all tight, makes me feel like nuts are not simply rotating counter-clockwise and off. It's a change between the rim holes and the nuts....I think they will get tightened, but I wanted to start over...