Broken/Stretched lug stud issue solved

[Qjake]

Uhhhhhh..What he said ^^

:iagree:

 

[GrantK]

At this point I think it would be easier to just weld the wheels on. :ybrick:

 

[Quentin]

Good time to post this for 1engineer, and others...from one of our writers named David Booth. Excellent read, (sorry about length).

The romantic view of engineering — if indeed there can be such a thing as a romantic view of engineering — is of the brilliant egghead toiling tirelessly in a lonely laboratory, the singularity of his or her genius conjuring up novel and unique ways to make his or her ever-evolving widget better. And, indeed, at the beginning of any engineering revolution, be it the first metal sword, the first airplane or the cars that are the subject matter of this column, the engineering world is full of ill-conceived contraptions as the adventurous but often misguided struggle to illuminate what is, at the beginning of any development cycle, a very long and dark tunnel.

Of course, if this is a soap opera, the script has to devolve into the romantic notion that (pardon my Ayn Rand) the purity of the singular genius is continually being thwarted by an evil collective. Thus, Charles Nelson Pogue’s infamous 100-miles-per-gallon carburetor was quashed by the might of the oil companies, Ferry Porsche’s iconic 911 has been supplanted by Cayennes and Panameras thanks to a committee of share-price-obsessed bureaucrats, and automobile design has become stodgily homogeneous because the large automakers are all in cahoots.

In reality, the homogeneity that purists so despise in modern automobile design is just the historical cycle of engineering development. At the birth of any technology, there are no rules, no guidelines and few expectations. Since whatever our mad genius is slaving over has not been done before, he or she can’t look back on previous developments, her or his drawing board literally the proverbial clean slate.

Of course, those same scientists, if they are at all competent, quickly dismiss failure. Engineers are nothing but clever backyard inventors who simply keep on trying different widgets until one doesn’t explode. (Thomas Edison is said to have tested thousands of potential fibrils before “cottoning” — almost by mistake — on to the carbonized bamboo filament that became the first successful light bulb.) The more brilliant — and, one presumes, successful — of minds quickly rejects the cockamamie and hones in on the probable. Throw in 100 years of failure, the processing power of supercomputers to weed out the improbable as well as constant refinement and what one gets in the “mature” phase of engineering is a general consensus on what works and what doesn’t. Compare any current technology — be it airplanes, automobiles or even the relatively new world of computers — to the same products in their infancy and you will find an incredible sameness to the modern as countless engineers rejected the mistakes of the past and converged on consensus.

The perfect automotive example of this evolutionary conformity is the recent introduction by BMW and Mercedes-Benz of small turbocharged fours in their entry-level luxury sedans. Once an idea singularly championed by Audi with its 1.8 and 2.0T fours, both BMW (in the X1, 328 and now 528) and Mercedes (C250) have abandoned their classic engine designs — normally aspirated in-line and vee sixes, respectively — for these same small turbocharged 1.8- and 2.0-litre engines.

The reason for this conformity is simple and essentially the same whenever any previously diverse product range becomes homogenized: The criteria set before the engineers became increasingly specific. In the case, for instance, of the 3 Series, C-Class and A4, all faced the same challenge — retain their previous powerful performance while meeting new, very specific fuel economy standards all without complicated and expensive hybrid or diesel technology. The key word in the previous sentence is “specific.” Chances are that, had all the manufacturers simply been challenged to achieve the best possible fuel economy for real-world conditions, their solutions might not have been so uniform. Each might have accessed its customer’s needs differently and come up with a different design.

But the fuel economy criteria that these engines were designed to meet are far more precise. Regulations governing fuel economy, it must be noted, are precisely defined test cycles that favour engines economical under light load conditions (low throttle openings at relatively low speeds), a forte of turbocharged engines. Whether these engines might actually improve real-world fuel economy appears to be incidental — or, at least, a secondary criterion. A cynic might even postulate that, like American high school curriculums, these new designs weren’t actually designed to improve the breed but rather pass some very specific tests.

And I think we can expect many more of these turbocharger-based solutions from our German friends. BMW is already in the process of dumping all its signature high-revving naturally aspirated engines from its M cars in favour of equally powerful but more EPA- and Transport Canada-friendly turbocharged variants. Audi already uses relatively small-displacement supercharged engines for its S-line and Mercedes has already started reducing the displacement of some its AMG models and slapping turbochargers under the hood.

That all three German luxury marques — Mercedes-Benz, BMW and Audi — have converged on exactly the same solution is simply the result of very specific requirements demanding a very specific solution. French philosopher François de La Rochefoucauld famously proclaimed that hypocrisy was vice’s tribute to virtue. Had Monsieur de la Rochefoucauld been an engineer instead of an autodidact, he might have instead noted that conformity is the price engineering pays for evolution.

[email protected]

Brilliant! I've speculated this many, many times due to the differences in EPA gas mileage ratings and CR's gas mileage ratings. This post just elegantly states it.

At this point I think it would be easier to just weld the wheels on. :ybrick:

Wouldn't be easier to rotate tires.

 

[1engineer]

Sorry to bring this up again but read this link in this post. http://www.toyota-4runner.org/general-discussions/117529-those-5th-gen-please-read.html

 

[brockeverly]

Sorry to bring this up again but read this link in this post. http://www.toyota-4runner.org/general-discussions/117529-those-5th-gen-please-read.html

Forwarded that company this link. Nice find.

 

[philsey]

So, what's the takeaway from this?

I thought sloppy work aka overtightening broke these. I've had 2 shops break 4 lugs, after I forewarned them, all the while swearing they used a hand tq wrench.

I am concerned that I'm driving on some stretched lugs.

I've owned a car since I was 16 (lessee, carry the 9, borrow the 1) that's FIFTY THREE years and who knows how many cars and tire changes that included! ... and I've never even heard of such a thing 'til my 5G.

Surely, Tacos, Sequoias, Tundras (maybe Lexii) use the same lug ... what gives?

 

[brockeverly]

We are now linked in their write up on the subject

 

[harper7]

Sorry to bring this up again but read this link in this post. http://www.toyota-4runner.org/general-discussions/117529-those-5th-gen-please-read.html

You notice they skip the very important part of the "How" the new studs were installed.No videos on that part so we don't know if it was done correctly and the damage was already done during the stud install.

They are an interference fit and if the knurles going in the hub are not lined up perfect they can be super hard to pull in.Technically, you are supposed to take the hub off and press them in from the backside not pull them in. Most mechanics choose the easy way,me included, and just use a stack of washers or a socket to fit over the stud and pull it into the hub til the lip on the backside sit's flush and yes ,sometimes they are a bee-atch to get in and could get over torqued putting them in. I've changed most of my past sports/race car's studs to ARP's so I've done a bunch and ARP's are more forgiving during install then oem studs.

Hard for me to buy into the" they are all bad from the factory" theory as I've had my wheels off my 5th Gen probably more then anybody on the planet. Being on my 6th set of tires(about to be 7 next week) and umpteen times times I've had them off rotating,changing suspensions ,diffs and such. If I were to guess I'd say at least 20 times per wheel and not one broken stud.One key thing is they were never over torqued.Do you really think I'm THAT lucky or that I just got lucky and got a good set? Has anybody heard of any breaking except during a wheel install and the wheel coming off?

 

[Qjake17]

^I'll agree with this^ But I don't think they would go through all the work of documenting the issue and the time spent speaking with Toyota and placing it on their site if they thought in any way they caused or contributed to the issue.

Also I too have had my wheels off many times, at least 8-9 per, and have used both an 85lb torque stick and since hearing of these issues a torque wrench @ 85 lbs and have not broken any studs. Like Harper suggests did I get a "good" set of studs or have I just been lucky.

 

[Antmanswife]

Agreed also. Antman's had his off about 5 or 6 times since new, and not one broken stud. "Most places can't be trusted to take the time to do it the correct way." he says.

Hence, stretched/broken studs.

 

[1engineer]

You notice they skip the very important part of the "How" the new studs were installed.No videos on that part so we don't know if it was done correctly and the damage was already done during the stud install.

They are an interference fit and if the knurles going in the hub are not lined up perfect they can be super hard to pull in.Technically, you are supposed to take the hub off and press them in from the backside not pull them in. Most mechanics choose the easy way,me included, and just use a stack of washers or a socket to fit over the stud and pull it into the hub til the lip on the backside sit's flush and yes ,sometimes they are a bee-atch to get in and could get over torqued putting them in. I've changed most of my past sports/race car's studs to ARP's so I've done a bunch and ARP's are more forgiving during install then oem studs.

Hard for me to buy into the" they are all bad from the factory" theory as I've had my wheels off my 5th Gen probably more then anybody on the planet. Being on my 6th set of tires(about to be 7 next week) and umpteen times times I've had them off rotating,changing suspensions ,diffs and such. If I were to guess I'd say at least 20 times per wheel and not one broken stud.One key thing is they were never over torqued.Do you really think I'm THAT lucky or that I just got lucky and got a good set? Has anybody heard of any breaking except during a wheel install and the wheel coming off?

You make very valid points and I did notice the initial install was not documented. I am impressed that someone actually took the time to document what they did though. We both know the only way to prove a problem like this is with proper testing in a lab. Maybe I will suggest this as a project in the ME lab at one of the universities. They would probably like a real world application.

 

[Vegas]

Installed spidertrax yesterday and looked on here to find out what size socket the lug nut is and what it gets torqued too... And gooooood god I found so much talk about people having issues with breaking lugnuts... 85 pounds did not seem like too much effort to get too and I wanted to crank it down a lot tighter for piece of mind but didn't want to break one.

 

[1engineer]

Bumping this up as a PSA for all the new guys out there. 83 is the magic number! Let's just say 120 will break them as I found out when the guys at a Mom and Pop shop were rotating mine a few months ago. They told me they broke two and were waiting for new ones. I asked them what they were torquing them at and they told me 120 was normal. I told them 85 and they looke at me like I had two heads.

 

[Mick1]

Yep, I had two broken and a couple stretched at the tire shop when the truck only had 1,000 miles on it.

After that I wrote "83 ft Lbs MAX" on the wheel lock key and then put packing tape on it to prevent the writing from wearing off. Have not had a problem again.

 

[Zeusmotorworks]

Coming from what I gleaned from dealing with various alloys of Aluminum, Titanium, and Inconel, one factor that either I missed here, or has eluded the conversation is "dissimilar metals". I have no clue what steels/coatings that are used in the studs and then in the lug nuts. However, one thing that appears to be constant is that more times than not the stud breaks when removing the lug nut vs torquing (ask the shop next time). Having experienced the same problem in the past with the Acura Integra Type R and Mitsubishi Rally cars (my business), then again with my sons FJ and Tacoma, I posed that maybe there was another answer. When fastening various parts of aero-frames together we were required to use a primer on the rivets. This helped prevent any reaction (oxidation) between differences in the rivets and parts they went though. With that thought in mind and my experience with the Acura and many, MANY Mitsus, since day one my FJs studs received a nice dose of 2000 degree copper anti-seize. Now before I'm assaulted with math, please understand that none of the vehicles that received this treatment suffered a single broken stud there after... ever! To this day, I've never had a customer come back to me, my own personal, or one of my kids cars have further issue. So with that said, I'll not get into an academic discussion, but will merely throw out lots of experience for others to consider in making their own decisions.

 

[Zeusmotorworks]

BTW, I torque to 85 and rotate every 5k of the vehicles lives

 

[DangerDanJD]

Bring back an old thread but interested to see if anyone is having problems these days. My 2017 4Runner has under 500 miles on it and two different shops have broken off lugs. I replaced the tires the day I purchased and the tire shop snapped one at 80lbs. I took it straight back to the dealer and they replaced the bad lug. One week later, I dropped the truck off at a different shop to have bilstein 5100's installed. Another lug snapped, again at 80lbs. I'll be taking it back to the dealer next week to see what they say.

 

[Zeusmotorworks]

Anti-seize on studs and tire rotation every 5000 miles-ish. No broken studs on 2 2007 FJ Cruiser's, 96 4runner, and a 2014 4runner. I'm starting to see a pattern ... but again what would I know, I only built aircraft. Same for my sons vehicles, after I started the anti-seize on their's. One sons FJ was obviously a coastal vehicle. First time wheels came off broke a few studs. No worries after the treatment though.

 

[BlackWorksInc]

Are we not overlooking the obvious here?

*Lube Tech Zaps Wheels on with 1/2" Impact Gun to probably 120ft.lbs, then uses Torque Wrench set to 83ft.lbs* It clicked! It's good! *Rinse & Repeat?*

Because honestly, that's probably about how it goes with most places... I had to point out to a couple of my lube techs at my old job that "yes it clicks, now set it to 110ft.lbs and check it, oh it clicks super easy then too? Sounds like it's over torqued".

Additionally the point about installing them is good, most guys zap them on with an impact (I'm guilty of this), though usually they sit on it for a bit (I prefer to get it so the back of the stud sits flush, after that I let torquing the nut to spec do the rest).

Something else to point out and I brought this up with an FTS once. The Tundra has two wheel options with two wheel torque specs. Aluminum is 97ft.lbs. Steel is 152ft.lbs, they don't have different part numbers for the studs last I checked. The difference seems to be in how the steel wheel "springs" more than the Aluminum one and that it uses a more conical style lug nut to seat vs. the wheel centering washer style the aluminum ones use. Apparently that's enough to NOT snap off the lug nuts when torquing it to 152ft.lbs on the steel wheels. Not sure if that's true or not, haven't honestly bothered to look into it deeper than that.

Anti-seize on studs and tire rotation every 5000 miles-ish. No broken studs on 2 2007 FJ Cruiser's, 96 4runner, and a 2014 4runner. I'm starting to see a pattern ... but what what I know, I only build aircraft. Same for my sons vehicles, after I started the anti-seize on their's. One sons FJ was obviously a coastal vehicle. First time wheels came off broke a few studs. No worries after the treatment though.

I assume then you've done the math and made a conversion from dry torque to equivalent wet torque for the specific anti-seize compound you're using on the lug nuts so they are set to the correct wheel torque and not over or under torqued, since you do build aircraft? What is the rough difference between the two? I've always been curious.

 

[Zeusmotorworks]

Are we not overlooking the obvious here?

I assume then you've done the math and made a conversion from dry torque to equivalent wet torque for the specific anti-seize compound you're using on the lug nuts so they are set to the correct wheel torque and not over or under torqued, since you do build aircraft? What is the rough difference between the two? I've always been curious.

You're ab so ****ing lutely correct that I did the math back then... and rounded it to something reasonably rememberable. However, I'm not gonna put down my wineglass, go find my old bottle of anti-seize, do an Internet search on its properties, and redo the math tonight... right now I'm doing good to get Siri to actually print what I say. However, most people that do not torque their own will never know specifically what the cause of the failure was. Because you're absolutely correct in that most "shop monkeys" are going to use a freaking impact to run the Lugnuts down.

<edit> For anyone wanting to have a technical discussion that I am and not in the right mind to have tonight, ponder this, will your particular compound increase or decrease the torque rating? You can't just assume.