Lug Nuts Again

[akaodie]

I have a question for the great people of this forum.
If a lug nut is over torqued by a mechanic, is the stud then stretched and have to be replaced? Or will just going back to proper specs work just fine?

 

[akaodie]

This may be in the wrong section, sorry I don't know how to delete my thread.

 

[stimpy]

once stretched it will not return to normal , its ussually bottlenecked or the threads are stretched and will not hold , most lugs are often overtorqued by the tire guys who think the tighter the better ... but lately I have noticed some shops are now using torque wrenches and doing the finishing pull .

 

[akaodie]

Thank you for the reply.
Does this mean I need to replace the studs on all my tires?

 

[LXCam]

How much are we talking, do you have any idea?

 

[akaodie]

Thats what I don't know, should I mic the studs and see if there is a thin spot and if not are they okay?

 

[Ole Slewfoot]

lay a new bolt against them. If the threads line up, it is not stretched.

Usually it seems if they were that tight, the nuts are first to give out, the tapered part gets crushed in, and becomes hard to thread.

 

[LXCam]

Sure can. Measure the outer most diameter, then just below where the lug made contact and towards the hub, that is where you'll see any stretch. You can also use a good straight edge and see, if its bad it'll be obvious.

Also what size are the studs?.

 

[akaodie]

These are from a Ford Exploder I bought used.

 

[kbs2244]

If you are that concerned just replace them.
They are cheap and it is not difficult.

 

[Rod N]

They would have to gone crazy torque to stretch the stud. Was it just hard to get off?
If the nut still goes on and off by hand it should be fine.

 

[theoldwizard1]

Stretched or just over-tightened ? To me, "stretched" would mean you could NOT apply additional torque because the threads were stripped. Good luck getting the nut off !

They would have to gone crazy torque to stretch the stud. Was it just hard to get off?
If the nut still goes on and off by hand it should be fine.

I CONCUR !!

 

[LS6 Tommy]

I've never seen whee studs stretch. I've seen many snap right off when they were over torqued or ones that were weakened to the point that they broke upon attempted removal of the nut. I've also had one snap off on the ride home from the shop...

Tommy

 

[Jack Olsen]

Do the studs hold the correct torque?

 

[akaodie]

I guess I was just concerned with me using proper torque and the coming loose because the studs are bad.

 

[akaodie]

Yes they have "held" so far just worried. I keep checking just to be sure. I am the only one responsible for my family safety. Thanks again everyone.

 

[landlord30]

I'd be worried about the holes on the rims too.

 

[RainierHooker]

If you were really concerned, I'd get all new nuts and check for run-on torque. Ratchet the nut down the threads of the stud with a low-unit torque wrench. If the threads on the stud are not worn, it should take no less than about 10 INCH/lbs but no more than 30 in/lbs to screw a fresh new nut onto them...

 

[WhiffySpark]

How do you know they were over torqued?

 

[CNGsaves]

OP . . . . since it's a Ford Exploder . . . . your worries are likely SUSPENSION !!

Pidgeon-toed lack of proper alignment and low tires . . .
. . . . . will roll-over that POS at first possum in road !!!

Put in 2 new studs and lugnuts across from each other on each wheel . . .
. . . continue to use rest of old studs and lugnuts.
/done

Heck, NASCAR barely has 4 lug nuts on at over 200 MPH !!!

 

[lynnbilodeau]

Little harsh on the Exploder.

Agree with Tommy. It may be possible to stretch one, but not likely.

As others have said, lay a bolt of the same size and pitch on the ones you suspect. It you fits up nice and tight, then it isn't stretched. I have seen guys twist them off by over tightening, but never stretched.

 

[ChevyEFI]

It sounds like OP has read in to erroneous TTY information strewn about the internet.

 

[akaodie]

It was just a concern with a used vehicle that I bought with no maintenance data. I guess I am just overly worried. Yes I have already done 3/4 of the wheel bearings and hubs with the last one sitting on the shelf in my shed. Bushings and shocks are next. Thanks again everyone.

 

[bigdav160]

1/2 inch x 20 wheel stud? Recommended torque for the size is 90 - 100 lb/ft. At about 600 lb/ft it will be permanently deformed.

But, once a bolt/stud is over-torqued it causes internal fractures. Eventually it will gain enough fractures it will fail.

Without removing the studs and putting them in a stretch gauge or Skidmore/Wilhelm bolt tester there no way to know if they are damaged.

If it worries you, I'd just replace them.

 

[akaodie]

Thank you, I think that will be on the list with the bushings and shocks. Give me a reason to build the press I have been wanting to build.

 

[IndyGarage]

1/2 inch x 20 wheel stud? Recommended torque for the size is 90 - 100 lb/ft. At about 600 lb/ft it will be permanently deformed.

But, once a bolt/stud is over-torqued it causes internal fractures. Eventually it will gain enough fractures it will fail.

Without removing the studs and putting them in a stretch gauge or Skidmore/Wilhelm bolt tester there no way to know if they are damaged.

If it worries you, I'd just replace them.

Wheel studs usually fail before the lug nuts fail, but not always.

They usually have very little "stretch" in the metal before they fail. They just break off.

Metal moves in two stages - first there is the plastic stage, where it can stretch and spring back. This stage does not damage the metal, but the distance is dependent on the heat treat and temper of the metal. Spring metal has a relatively long plastic stage. Hardened steel has a very short plastic stage.

If you go beyond this stage - even just slightly, then you start fracturing the grain boundaries of the metal, and those fractures weaken the metal. Again, on harder material, the grain boundaries will tend to fracture all at once, causing the metal to break. On softer or more tempered metal the fracture is more "gummy" in nature (think of breaking a piece of coathanger wire - it's soft and doesn't just split in two).

Wheel studs are both hard and soft. The threads are rolled so they are work hardened, so the surface is relatively hard and won't stretch much. The center of the stud is softer, so it has a bit more stretch.

This makes studs pretty tough, but once you've stressed them too much, they tend to fail pretty easily.

If you've truly over torqued (it takes more than just a few foot lbs) the studs they should be replaced. Also, inconsistent lug torque often leads to warped rotors and vibrating brakes.