spontaneous wheel stud sheering?

[Chrisleduc1]

Slightly off topic (ok waaay of topic), but wanted to post here for initial attention since there are so many knowledgeable guys here...

What are the odds to having 2 wheel studs snap? Spontaneously?

I went to drive my wife '18 odyssey and noticed a lug nut in the cup holder, but it was snapped off. My driveway is uphill, and off camber. It was the front driver, the downhill side of the driveway. My wife said, "some ladies were walking by a few days ago and they called out from the street (downhill about 25 feet in distance) 'is this yours?'" They handed her the lug nut and my wife thought it was a random bolt from when I moved a trailer the other day.

So short story long, as I look at this front wheel, there are two studs that are snapped off, side by side. The one nut was recovered from down in the street a few days ago, but not the other.

I do swap sets of tires, and did a swap about 6-9 months ago. However I do use a torque wrench and make sure I have it right..

I guess one could have snapped while driving and then the other while going in and our of the driveway..? I am having a hard time seeing how this could happen without someone having come during the night and done this.

Thoughts?

 

[TeCKis300]

From my experience and many anecdotal stories, some from cars used on a race track...

The primary cause can generally be traced back to undertorqued lug nuts. Overtorqued lugs, even overtorqued by a significant margin don't usually fail in this manner. Undertorqued lugs will do this just about every time.

As torque wrenches generally wear and fail in the lower direction, unless you've recently calibrated your torque wrench, I'd recommend always shooting for some 10-20% higher torque to compensate. Even if the wrench was on point, 10-20% more than spec is still well within reasonable and safe torque range.

 

[Chrisleduc1]

@TeCKis300 I did go out and check the remaining ones, but just with a standard tire iron. One was very loose, the other 2 very tight. I need to go check the others.

The torque wrench is fairly new, used only a handful of times. I cannot remember where I bought it - could be an amazon chinese product...

So you'd say spontaneous breaking without any malicious activity is a realistic possibility?

 

[TeCKis300]

Realistic and very likely.

Reason being when lugs are torqued, bolts work strictly in tension, and other directional forces are transferred via the hub mating surface.

When bolts are loose, the lugs work in shear which they are weak to, for load support, transfer axial torque i.e. acceleration/braking, and any suspension motions. This effectively bends the studs back and forth as the wheel goes round and round, fatiguing the metal. Where bolt threads now also create easy stress risers to facilitate breakage.

 

[Chrisleduc1]

From what I can tell, I was using this Husky 20-100lb wrench. The spec on this vehicle is 94lbs and from other counsel I just received, these tend to decrease in accuracy as you get to the outer edges of their capacity...?

Husky 20 ft. /lbs. to 100 ft. /lbs. 3/8 in. Drive Torque Wrench H3DTWA - The Home Depot

The Husky 3/8 in. Click Torque Wrench has a range of 20 ft./lbs. to 100 ft./lbs. and is made of alloy steel construction for strength and long-lasting performance. It also comes in a hard plastic storage

www.homedepot.com

 

[Chrisleduc1]

Since I had the torque wrench in hand, I check all the nuts. Granted, it could be off. All lugs on the other 3 wheels were at least 94 (spec) according to this wrench. The nut that was loose on the wheel in question was still a quarter turn short of spec, after I tightened it yesterday. The other remaining 2 were at least at spec.

 

[indycole]

I had a similar issue many years ago using a Tekton wrench on a different vehicle. I now use both Snappy and Precision Instruments wrenches to stay in check. I still had the Tekton when I bought the other brands and it turned out to be like 30% off. It may have very well been poor maintenance/treatment of the wrench but I haven’t had any issues with the better brands. The Precision Instruments wasn’t off at all last time I had it calibrated.

 

[TeCKis300]

I've been meaning to calibrate my torque wrench as I've had it for many many years. I usually set it to 10% higher than my target as I know it's likely worn.

Thread is a good reminder for me to calibrate it. Going to use this method:

 

[KLF]

Seems like the first thing to do there is calibrate that cheapo luggage scale. Kinda a leap to assume it's accurate.

 

[bloc]

All of the studs on that wheel need to be changed ASAP, ESPECIALLY before your family goes anywhere in it. Even if they haven’t broken yet there is a good chance they have been stressed in ways they weren’t intended and could fail in the future.

And yeah, this isn’t 200-series tech but basically the exact same thing could happen to one.

I have two neiko pro torque wrenches, and both were dead-on in calibration when I checked. Unless I splurge on snap-on or similar I always do a home calibration when I get them to see if they are in the ballpark.

This also makes me realize I’m up to five torque wrenches at this point. What a “hobby”.

 

[KLF]

Many years ago I sent all my torque wrenches out to be checked. I had a few Craftsman, one Snap-On, and one big Matco. The well-used Craftsman ones were shockingly close, the Snap-On was OK, needed a tweak. But the expensive Matco was way off. Go figure.

I have one of these:

Amazon product ASIN B009GLISI0
I've tested it similar to the method above, except I mounted it in a HUGE bench vise and used a breaker bar and a 5-gal bucket that I would trickle water in until it got to the target torque, then weighed the bucket on a lab-grade platform scale I borrowed from the chem lab next door. It was super close, withing my tolerance needs.

 

[TeCKis300]

Got my $8 luggage scale from Amazon. Calibrated an old 50-250 ft/lb Husky brand torque wrench that I've had at least 17yrs now. It was pretty much spot on. I set it to 100 ft/lb, and pulled from the 2 ft mark at the handle.

Clicked at 51.2 lbs pull, less than 2% off, on the high end, or within measurement error.

Now I can go forward with confidence, knowing my torque wrench is calibrated.

 

[bloc]

Also if you ever need to accurately torque a reverse-thread bolt the weight @ given distance method is about the only way, without investing in a one-use tool anyway. I did this recently on a motorcycle.. breaker bar, shifter kart axle, 35# kettlebell, tape measure, calculator. Bam, 120ft-lb.

 

[KLF]

Also if you ever need to accurately torque a reverse-thread bolt the weight @ given distance method is about the only way, without investing in a one-use tool anyway. I did this recently on a motorcycle.. breaker bar, shifter kart axle, 35# kettlebell, tape measure, calculator. Bam, 120ft-lb.

Your torque wrenches don't work in the opposite direction? Mine do. Reversible ratchet head. Or are you saying they can't be trusted in that direction?

 

[bloc]

Your torque wrenches don't work in the opposite direction? Mine do. Reversible ratchet head. Or are you saying they can't be trusted in that direction?

Unless they explicitly say they are good for both directions they are not to be trusted, but you can calibrate both directions if you are unsure.

Many of them have a force sensing mechanism that is asymmetrical, or at least used to. My dads old click wrench that eventually died and I took apart to see how it works when I was about 16 was definitely not the same in each direction.

Plus in the case of my big split-beam wrench, simply can’t go reverse.. the ratchet doesn’t even reverse.

 

[KLF]

Well I don't remember ever using them in left hand thread situations, but now you have me curious. I'll use my digital torque meter to see if they are the same in both directions.

(my first car, a '63 Pontiac had LH threaded wheel studs on the left side of the car. I know big rigs and many trailer still do this)

 

[jeproks]

Couple of the Costco tire center I go to have torque wrench calibration tool on the waiting area. I asked if I can bring my wrenches to calibrate and was told yes.

 

[bloc]

Couple of the Costco tire center I go to have torque wrench calibration tool on the waiting area. I asked if I can bring my wrenches to calibrate and was told yes.

That's a great idea.

BTW most tire shops I've seen use split-beam because they easily adjust, retain calibration well, and don't need to be set to 0 between uses to maintain calibration. Big part of what pushed me to get one for my higher torque jobs.

 

[TeCKis300]

I was curious about the bi-directionality of my torque wrench. Set it up to measure again. 50.6 one way, 52.2 the other way. Functionally equal within the limits of my measuring methodology. At least that's for my specific wrench. My 3/8" beam wrench is also bi-directional as it has a scale in both direcitons.

 

[bloc]

I was curious about the bi-directionality of my torque wrench. Set it up to measure again. 50.6 one way, 52.2 the other way. Functionally equal within the limits of my measuring methodology. At least that's for my specific wrench. My 3/8" beam wrench is also bi-directional as it has a scale in both direcitons.

Beam is great but in the lower ranges you must be careful to keep the handle parallel with the metal bar going into it.. they are often hinged. If you twist on that thing it can throw off the reading. I have one that is 0-80 in/lb for setting up differentials that only has a round knob for the same reason.

I'm not sure of the brand but we got a very cheap 10-80 clicker on amazon to set the saw blades on my ladder truck and it explicitly said it was only accurate the normal direction. We're talking a $30 tool though.