tightening torque for wheel lugs

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Intetesting! I recall reading somewhere that if you lube or add anti seize lubricants to the studs, you will have to torque it %15-20 higher because of the lubrication. it made sense to me on the surface. Maybe there is more to it.
Maybe for the trucks, they specify a higher torque due to lubrication ... idk
 
Originally Posted by OilUzer
Intetesting! I recall reading somewhere that if you lube or add anti seize lubricants to the studs, you will have to torque it %15-20 higher because of the lubrication. it made sense to me on the surface. Maybe there is more to it.
Maybe for the trucks, they specify a higher torque due to lubrication ... idk


Nope, wrong way.

lubricating threads REDUCES the torque needed to get the stud stretch to provide the proper clamping force.
 
Originally Posted by zeng

At 107 Nm for a 12 mm diameter size or 79 ft lbs for half inch diameter bolt, how would one calculates its axial force and tensile stress ?
Anybody care to explain ?


zeng...HAve finished reading the Invisible's omnibus (my ambition for the Christmas break), and have re-engaged engineer head and have bashed together a very rough presentation on the process, and hope that it helps...

….now for the disclaimers
* this does not constitute medical, maintenance (or engineering advice)
* while it uses scary numbers and facts, it is NOT using the actual pitch dimensions etc. of real fasteners. The rough numbers are used to convey the process, and are (heavily) rounded for convenience in using my Windows 10 Calculator and memory (the 15C and notepad are still in my work bag)
* the use of scary numbers was not to intimidate, nor scare people who don't do numbers, but rely on gut feel, and the fact that however dubious their processes are "nothing blew up in the past, so I'm therefore right...on every topic that I decide to have a tanny in.
* It's (hopefully) obvious that I've not included anything to do with the friction of the nut against the wheel, whether that be a flatnut/washer, or a tapered cone...they ALL affect the outcome seriously.

Bolts Basics.jpg
 
zeng,
having done calculations on thousands of bolts in my turbine engineer career, I much prefer angular rotation as a tightening regime.

Using the above, you can see that every 360 degree rotation of the M12x1.5 nut "stretches" the stud by 1.5mm.

My turbine bolts needed to be installed at 0.15% STRAIN to provide the appropriate clamping force and high temperature life.

So if you had an M12x1.5 that was 100mm long, and needed to install it at 0.15% strain (elongation), you would need 0.15mm of elongation, or 0.15*306/1.5....36 degrees rotation.

Irrespective of surface condition or treatment.

(Turbines, we pulled the casings together using the studs and nuts until they were tight. Then backed them off individually, and finger tightened them to 200ftlb. Heat them up (elongating them to take the nut friction off), then move them to the desired angle, let them cool and you are done).

Now the heating process that made tightening easy for sure also meant that the nut and stud weren't installed with residual torque strains that would add to the triaxial stresses, and reduce life and lead to loosening.

So YES, I agree with going back and having another check when the wheels have worked a bit...we scraped every surface before reinstalling...none of us do that with our wheels and hubs.
 
Originally Posted by kschachn
Originally Posted by Trav
I know you are not an experienced mechanic or a mechanic at all but seriously you need to stop. Don't run this garbage you are posting on and on because you cant/wont admit you are wrong under any circumstances as usual, just post your videos and finding problems with your new car and leave advise on wrenching to others that know what are doing.

I was thinking the exact same thing. This user sounds quite familiar..


Given all the other threads, I'm giggling through this as well.

It's a pattern for sure.
 
Originally Posted by Shannow
Originally Posted by zeng

At 107 Nm for a 12 mm diameter size or 79 ft lbs for half inch diameter bolt, how would one calculates its axial force and tensile stress ?
Anybody care to explain ?


zeng...HAve finished reading the Invisible's omnibus (my ambition for the Christmas break), and have re-engaged engineer head and have bashed together a very rough presentation on the process, and hope that it helps...

….now for the disclaimers
* this does not constitute medical, maintenance (or engineering advice)
* while it uses scary numbers and facts, it is NOT using the actual pitch dimensions etc. of real fasteners. The rough numbers are used to convey the process, and are (heavily) rounded for convenience in using my Windows 10 Calculator and memory (the 15C and notepad are still in my work bag)
* the use of scary numbers was not to intimidate, nor scare people who don't do numbers, but rely on gut feel, and the fact that however dubious their processes are "nothing blew up in the past, so I'm therefore right...on every topic that I decide to have a tanny in.
* It's (hopefully) obvious that I've not included anything to do with the friction of the nut against the wheel, whether that be a flatnut/washer, or a tapered cone...they ALL affect the outcome seriously.



Oh gosh, heaps of thanks Shannow.
Let's see if I could wrap my head around this.
 
Originally Posted by OilUzer
Originally Posted by MasterSolenoid
Originally Posted by Pelican
Originally Posted by demarpaint
I use one for torquing lug nuts. I go by what the mfg. of the vehicle specs.

Absolutely! The torque is there so that over tightening doesn't occur which could warp the brake rotors.

I agree, and that's why I use a Torque Wrench on Lug Nuts.

Newton Meter converted to Ft. Lbs.
88 NM = 65 Ft Lbs
107 NM = 79 Ft Lbs
--------------------------
200 NM = 147 Ft Lbs

Diameter of Stud would also factor into proper torque.

Tire change places want you to come back after a few days so they can RECHECK the torque.
They know lug nuts may loosen.


Ou r Tuscon spec is exactly 65-79 ft.lbs in the owner's manual! Same as your kia.
I Try not to go over 73-75 but tire shops do it at 80 and won't listen to what you have to say. One of them said that's what their books show and legally they have to torque it to 80. Not a problem just 1 over 79.
147 is not a good idea!
This is interesting. I'm wondering about the European torque specs for the Kia. 80 N-m = 59 ft-lbs, and 107 N-m = 79 ft-lbs. That sounds a bit on the low side. I wonder if these are small wheels - perhaps 14 or 15"?

The range for our Mazda 5 (16" wheels) is 65 - 87 ft-lbs. I tighten them to 80 ft-lbs.

I go in 20 ft-lb increments - that is, 20, 40, 60, and 80 ft-lbs. I check them after about 100 km, but have never found them to come loose after being tightened with this method.

I have had the lug nuts on alloy wheels loosen up when I went by feel rather than using a torque wrench.

As others have mentioned, torquing them tighter than spec can warp the rotors and/or stretch the studs, as well as making the nuts impossible to remove with the tire changing tools in the trunk.
 
Originally Posted by BobGoblin
OK, I torqued all my nuts to 110 Nm. I will drive a few days and re-torque again to check for loose nuts.


Good idea. It takes a whole 2 minutes for peace of mind. Idea for convenience: leave the torque wrench under your seat for a week. After a few days of driving, check it again. It would take less than 2 minutes.
 
Originally Posted by StevieC
Why do they have a Torque Spec then? Well because they need to convey to someone else approximately the force used in some manner but aren't needed above common sense when it comes to things like lug nuts or oil drain plugs for example. Not torquing these things and using reasonable force that is "plenty" but not "over tight" is more than enough.


They have a torque spec because they are supposed to be torqued, in sequence, to that spec to provides the proper amount of even clamping force for the wheel/rotor/hub assembly. Any decent dealer will always use a torque wrench on the wheels and will require you to come back in ~150Km to have them re-checked. Torque spec varies massively depending on application and stud size, fastener type...etc. Most dealers also won't let you use the same lug nuts for summer aluminum and winter steel wheels, because of the difference in how they seat.

Using an impact and just blasting them on is simply lazy and, for someone who is openly proud of being so anal-retentive/OCD, I'm quite surprised that you not only find this satisfactory but in fact endorse it
21.gif
 
I love my 4 torque wrenches.
There are some experienced wrenches out there that can torque a wheel fairly evenly by hand.
My older brother was one.
But most people cannot and no one can match the evenness of a torque wrench used properly.

Just my 2 cents...
 
Can't have too many torque wrenches (I have 5). If I can find the correct torque for any fastener on my vehicles, I will use the appropriate wrench. Interestingly, the correct lug nut torque for my current and recent FCA vehicles is 130 Ft Lbs (2014 Ram, 2015 Challenger, 2016 Charger, and 2018 Jeep GC). When remounting wheels, I start by finger tightening the lug nuts as much as possible. I then use my electric impact wrench set at 60 Ft Lbs to do an initial tightening. I finish with my torque wrench and set them at exactly 130 Ft Lbs. I then drive the vehicle for a few miles and check the torque again. About a week later, I check the torque one more time.

TorqueWrenches.JPG
 
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Just thought of something else, the coin or mating surfaces of nut to wheel should be clean and dry and not galled or otherwise damaged. Also when using a tourque wrench you will usually notice without looking when the appropiate torque has been reached. Some call this muscle memory but of course no one would ever rely on this---- right?
 
Originally Posted by OVERKILL
Originally Posted by StevieC
Why do they have a Torque Spec then? Well because they need to convey to someone else approximately the force used in some manner but aren't needed above common sense when it comes to things like lug nuts or oil drain plugs for example. Not torquing these things and using reasonable force that is "plenty" but not "over tight" is more than enough.


They have a torque spec because they are supposed to be torqued, in sequence, to that spec to provides the proper amount of even clamping force for the wheel/rotor/hub assembly. Any decent dealer will always use a torque wrench on the wheels and will require you to come back in ~150Km to have them re-checked. Torque spec varies massively depending on application and stud size, fastener type...etc. Most dealers also won't let you use the same lug nuts for summer aluminum and winter steel wheels, because of the difference in how they seat.

Using an impact and just blasting them on is simply lazy and, for someone who is openly proud of being so anal-retentive/OCD, I'm quite surprised that you not only find this satisfactory but in fact endorse it
21.gif


Like I said to Trav, no harm done torquing it. But in the 37+ years I have been around (28 of them learning/working with my dad on the side and full time at times) and the 50+ years my dad has been a licensed mechanic he hasn't torqued the wheel nuts and 0 issues, 0 lawsuits, 0 comebacks. I'm not saying don't do it, but that we haven't and had no issues because we double check each nut a 2nd time with the gun at full power for a short blast.

The tires on my Caravan when I took them off to put my Snow tires on were so tight I had no choice but to use a breaker bar to get them loose on 3 wheels and the 4th wheel was fine with just the impact gun so clearly they weren't torqued properly from the get go. I put them back on with a high torque battery powered impact driver in the method I have described and drove them 10,000km (6K miles) 0 issues. I then pulled them all off at the last oil change and rotated the fronts to back and put them back on and it has been 3,000km and 0 issues and I'm sure it's not what FCA spec is nor was it the case on my Journey either. Also 0 issues. Also 0 issues on my Santa Fe with multiple sets of tires, rotations etc.

Here is what FCA calls for for my '18 Caravan... Which again I assure you mine aren't tightened to this spec I'm sure and no wheels popping off. And again I'm not against Torquing them, adding a step for safety is always a good thing. It's just my opinion and mine alone it's not needed is all. To each their own with what they are comfortable with.


Wheel Torque.png
 
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Originally Posted by Shannow
hmmm, nothing blew up and no lawsuits...the new BITOG gold standard of doing things.

Scary.................
 
Originally Posted by Shannow
hmmm, nothing blew up and no lawsuits...the new BITOG gold standard of doing things.

And why do engineers have liability insurance?
 
Originally Posted by SilverSnake
Can't have too many torque wrenches (I have 5). If I can find the correct torque for any fastener on my vehicles, I will use the appropriate wrench. Interestingly, the correct lug nut torque for my current and recent FCA vehicles is 130 Ft Lbs (2014 Ram, 2015 Challenger, 2016 Charger, and 2018 Jeep GC). When remounting wheels, I start by finger tightening the lug nuts as much as possible. I then use my electric impact wrench set at 60 Ft Lbs to do an initial tightening. I finish with my torque wrench and set them at exactly 130 Ft Lbs. I then drive the vehicle for a few miles and check the torque again. About a week later, I check the torque one more time.


Your process is incredibly similar to mine
thumbsup2.gif
 
Originally Posted by StevieC

Like I said to Trav, no harm done torquing it. But in the 37+ years I have been around (28 of them learning/working with my dad on the side and full time at times) and the 50+ years my dad has been a licensed mechanic he hasn't torqued the wheel nuts and 0 issues, 0 lawsuits, 0 comebacks. I'm not saying don't do it, but that we haven't and had no issues because we double check each nut a 2nd time with the gun at full power for a short blast.


I'd hope there'd be no harm in torquing them, given that's the correct way to do it
wink.gif


I learned from a Master Tech in high school (took auto shop) and he was very particular about torquing things, surface prep...etc. All the best mechanics I know that work for Chrysler and Mercedes, as well as my buddy Jon, who has every Cummins cert under the sun, rely on their torque wrench where it is called for and that includes on wheels. It's been a common theme I've observed: Those that are extremely particular about their work tend to sweat those extra details. I'd be interested to hear if cinebarger torques wheels, since his work seems to be top-notch from what I've seen on here.

The issue with over-torquing is that you damage the mating surface on the wheel where the taper of it and the lug nut contact. You also risk damaging the threads in the nuts, which is something I've seen first hand with lads that are big fans of the impact and I wouldn't let near my wheels. It doesn't mean the wheels are going to fall off. It doesn't mean you'll get sued or get a comeback. Most folks aren't that particular and certainly aren't inspecting their wheels or nuts. It works, but it's not the right way, that's why they have a torque spec, and that's why that spec is NOT the same for every vehicle.
 
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