Torque wrench on lug nuts?

[Brice Rogers]

I think that the people who are rotating tires and tightening lug nuts are at the bottom of the mechanic scale - - probably an entry-level position.

One time I tried to loosen a lug nut after a tire rotation. I was using a 15" star spanner (X-shaped) and the lug nuts were so tight that it twisted the wrench permanently and I still couldn't get it off. I think that I put a torque wrench on it and it wouldn't budge at 200 f.p. So, I took it back to the Big-O (IMHO, that means Big zero) and had them use their impact wrench to loosen it. Then the fun began - - I wanted to do my own torquing of the nuts now that they were broken free. They refused to let me leave the shop unless they retorqued the nuts. I positioned myself between the wheel and the guy with the wrench and told him that I was going to retighten the lug nuts and that they would "have to go through me physically" if they tried to proceed.

Those guys were Neanderthals. They broke a power seat by forcing it and gouged a $200 Corvette aluminum billet wheel (which I made them replace).

Recently I went to a Chevy dealer to get tires rotated. I put paint spots on tires to make sure that they rotated the tires. Guess what ? They didn't. I raised a stink and then they rotated the tires - - except that they didn't follow the rotation order that is in the owner's manual. Is that important? Who knows. But if it isn't, why bother putting it in the manual.

So, I think that the underlying problem is that tires are rotated and nuts tightened by entry-level (probably minimum wage) "mechanics". These folks probably have less knowledge and experience than most on this forum.

[Ole Anderson]

I think that the people who are rotating tires and tightening lug nuts are at the bottom of the mechanic scale - - probably an entry-level position.

So, I think that the underlying problem is that tires are rotated and nuts tightened by entry-level (probably minimum wage) "mechanics". These folks probably have less knowledge and experience than most on this forum.

The issue isn't entry level mechanics, it is entry level management. Mechanics will do what they are trained and expected to do. If management isn't following up and performing any quality control, it is on them. And not just store management, upper level district and national management for the big boys.

[Tom Giles]

After a career as a jet engine technician I always properly the lug nuts. This is especially important for aluminum wheels. And I’ll bet there isn’t a tire tech anywhere the knows how to properly use a torque wrench or actually has a calibrated torque wrench.

[Michael Drew]

Interesting discussion. Seems like a lot of people are saying the same thing, just differently...

For what it's worth, I have a background in mechanics. Millwright, engine builder, rotating machinery (turbines and pumps, etc). I too use a torque wrench on my vehicle lug nuts. I have two sets of wheels / tires for my daily drivers. Winter/summer. I also like to use a light coat of anti-seize, although it really isn't needed with modern wheel studs, as they have a pretty good galvanic coating on them anymore. Unlike pre-2000's vehicles.

It's been mentioned a few times already, and correctly so, that there is an element of friction to consider when applying torque to a fastener. And yes, it does make a difference. A significant amount in most cases, so one should find the appropriate torque values with/without lubricant. And yes, anti-seize is considered a lubricant. Also know that the lubricated values on a torque chart assume that lubricant is between the nut and washer and/or bearing surface in addition to the threads.

Torque values corollate the amount of stretch a stud/bolt will see when the nut is twisted. That stretch is then used to determine clamping force. For example, a turbine case might use 3" diameter studs, it can be impossible to get a socket on them, so we use special nuts that have jacking screws to push the nut up, stretching the stud. We measure stud stretch and use that to determine recommended clamping force. Rod bolts in a typical engine are torqued while using a stretch gauge to get the proper stretch value. GM LS engines use what's called "torque to yield" head studs. You torque them with an angle torque wrench. The stud is torqued to a value xx, then an additional amount of rotation is applied in degree of angle. These are single use studs and are discarded after a single use. Same with GM suspension bolts. They are single use, torque to yield fasteners. GM instructs the use of oil for lubricant as well.

There are pneumatic, hydraulic and battery torque tools that can be set to get the desired torque values, but they are not the typical kind you might see in a garage, and rather expensive. My department uses a few of them for large bore pipe fitting. Here is a link to one of the suppliers we use:
https://hytorc.com/pneumatic
https://hytorc.com/lithium-series-ii

[Edward Weber]

Here is a slightly different perspective on this. Those who are familiar with large truck maintenance are probably aware of this already or should be. If there is ever an issue, it can become a legal issue.

https://www.fleetowner.com/equipment...bunking-a-myth

[Stephen Rosenthal]

I used to do a lot of my own car repairs (pre- computer everything) and never checked the torque. But then I bought a BMW along with the official service manual and noticed that the recommended torque setting was listed for every nut and bolt. Needless to say, I bought a needle beam torque wrench. Got a NIB Made in USA 1/2” Craftsman for $10 at an estate sale. Now I use it all the time. Works great.

[Brian Elfert]

I have a motorhome that takes 500 ft lbs of torque on the lug nuts. Tire shops will use a 1" impact to install the lug nuts and then check them with a torque wrench. A torque wrench isn't going to tell you if they are over tightened! A tire shop flunkie snapped off a brand new wheel stud on my motorhome that I had just installed. Way too much torque was applied.