[The_K_Man]

Hypothetical Lugnuts Question:

On a car with relatively low mileage, say 50-100,000 miles, the lugnuts were, for most of that period, consistently overtorqued to as much as 150 ft/lb, by shops where the car’s owner had tires replaced and rotated.

Now the owner decides they want to take on some basic maintenance tasks, including tire pressure, changing air filters, etc. etc. They find out that the correct torque for their make/model vehicle is under 100 ft/lbs, maybe 70 or 80ftlbs.

Is it ok to torque wheel lugnuts, that have been overtightened for years, to their lower, recommended torque.. or.. should they be torqued 5-10ft/lbs over, just to be on the safe side?

 

[mtts60]

"Just to be on the safe side" is already included in the specified torque value. So, no need to go higher.

Airplane wings are designed this way. Design load = 100%, but they are required to survive a load of 150%.

 

[The_K_Man]

"Just to be on the safe side" is already included
in the specified torque value. So, no need to go higher.

Airplane wings are designed this way. Design
load = 100%, but they are required to survive a load of 150%.

So no worries about long-term stretching/ elasticity strain, from lugs that were in a constant state of 200 ftlb hamfistedness? 😆

 

[mtts60]

If you're that concerned, buy new lug nuts, but make sure they're of the ball-seat design that pretty much only Honda uses.

Me? I wouldn't worry.

 

[Miker]

Are the lugnuts hypothetically tightened onto an aluminum alloy wheel OR a steel wheel?

 

[Hudouc]

This is basically exactly what I went through. You'll be fine. I torque my lugs to 85, and have never had it come loose.

 

[The_K_Man]

Are the lugnuts hypothetically tightened onto an
aluminum alloy wheel OR a steel wheel?

Alloy. But what would the scenario be with old fashion steel rims?

This is basically exactly what I went through. You'll be
fine. I torque my lugs to 85, and have never had it come
loose.

Same here! 82-83 for 80 ft/lbs. I don’t know how the previous owner kept my lugs torqued.

Like with tire pressure, it’s ok to go a ‘couple over’ with wheel lug torques. But not to go wild! 😆

 

[Miker]

Alloy. But what would the scenario be with old fashion steel rims?

Steel rims use different lugs (conical) and steel doesn't distort as easily as alloy. It can distort but a thing called aluminum creep and extrusion is what I would be concerned about.

A 12mm lug torqued to 80 lb/ft has a clamping force of 10160 pounds. IN GENERAL not including friction, lubricity, plating, etc
A 12mm lug torqued to, can't believe it went to 200 lb/ft, but it reaches to 25423 pounds.
Aluminum has a propensity to extrude and creep.
Since these are hemispherical lugs used on the alloy wheels it is possible that the aluminum extrudes and creates a deeper well. Not by much maybe but it may be damaged.
IF it opens the diameter a bit and you now only torque to 80 lb/ft, you are not seating the lugs properly to the wheel.
There is also the possibility that at 200+ there MAY be micro-cracking going on in the alloy wheel at the point of contact with the lugnut.
The lugs probably can withstand the tension applied to the threads but with the higher tension applied, the bolts could be fatigued from the heat/cool cycles of the brakes, etc. This fatigue reduces the shear strength of the bolts too.

Your hypothetical question of 50k-100k miles means the wheels spun around 39,550,000 - 79,100,000 revolutions (I calculated a std 215x55/R17 tires - 791 revolutions per mile)in those hypothetical miles. That's a LOT of shear force being applied on those extremely overtorqued lugs/studs.

Are we sure they were torqued that high ? 200+ ?

There are limits to all this stuff and even if the lugs can handle the tensile forces and not distort the threads on either the stud or lug, it's not good practice to bring the materials to their maximum limits. There's a reason for safety limits and at 200+ lb/ft I believe you are dangerously close.

Anyway that's my opinion. Hypothetically, that is!!!! - take it or leave it.

 

[Mr. Slowly]

I torque the lugnuts on my 30-year-old 190k mile Acura to 88 foot pounds - the factory recommended - and nothing bad ever happens. I never find a loose lug the next time I'm removing a wheel. The oil pan drain bolt wore out first... so now I have a younger, lower mileage oil pan and drain bolt.

 

[The_K_Man]

My takeaways so far from this conversation - especially given the critical information in post #8:

- Alloys/aluminum/etc. are more malleable than steel.

- Ergo, it is probably prudent, on a car you didn’t drive new, equipped with the original alloys, to over torque the wheel lugs slightly over spec., IE: 83-85 if the spec was 80 ft/lbs. 105 if 100 ft/lbs.

Even with steel rims on a car you are not familiar with the maintenance history of, it’s probably ok to go 1-2 ft/lbs over spec.

That’s what I’ve gleaned, and what my stomach tells me, and they’re in agreement! 😀

Are we sure they were torqued that high ? 200+ ?

Again: hypothetically.

And these days? Nothing would surprise me!

Except maybe a car that has had everything adjusted exactly to spec since new - original size tires to exactly recommended PSI cold, lugnuts at or just 1ft/lb over factory spec.

Because afterall, everyone knows better than the car maker, and its engineers, how much air to put in tires, or how much to torque wheel lugs to, etc. 🤪

 

[2Accordz]

Welp,
If the bolts are already "over-stressed"(hypothetically speaking, of course) then it's not really prudent, to be continuing to over-stress them..after re-installing the wheels...
I'd just follow the correct spec when you re-install them.

 

[AlanTheBeastV2]

Hypothetical Lugnuts Question:

On a car with relatively low mileage, say 50-100,000 miles, the lugnuts were, for most of that period, consistently overtorqued to as much as 150 ft/lb, by shops where the car’s owner had tires replaced and rotated.

Now the owner decides they want to take on some basic maintenance tasks, including tire pressure, changing air filters, etc. etc. They find out that the correct torque for their make/model vehicle is under 100 ft/lbs, maybe 70 or 80ftlbs.

Is it ok to torque wheel lugnuts, that have been overtightened for years, to their lower, recommended torque.. or.. should they be torqued 5-10ft/lbs over, just to be on the safe side?

If you mean 150 ft-Lbs as the set torque I'd not be esp. worried for a Honda Accord which 80 Ft-Lbs in pretty much all cases over the past ... 20 years?

If you mean 150 + 80 = 230 ft-Lbs then I'd replace the studs and lugnuts.

If there is plastic deformation the studs will be elongated.

1. Compare the length of the studs from the hub against another Accord of the same year. If there is more than a mm or 2 difference I'd replace them and the lugnuts
2. Compare the thickness of the studs along their length with a micrometer. If there is a deviation of more than about 0.3 mm (in a given stud) I'd change them and the lugnuts. Will be difficult to measure in the threaded area, however.

There is no danger in going 10 - 15 ft-Lbs over spec.

We changed to summer tires last weekend. My SO's new HR-V had the new tires put on rims and installed at Costco in the fall. Front left was way over-torqued on all 5 nuts. Other 3 wheels were norminal. So I guess they do it in teams.

Next time I'm at Costco I'll be visiting the wheel shop for a wee chat.

Steel rims use different lugs (conical) and steel doesn't distort as easily as alloy. It can distort but a thing called aluminum creep and extrusion is what I would be concerned about.

A 12mm lug torqued to 80 lb/ft has a clamping force of 10160 pounds. IN GENERAL not including friction, lubricity, plating, etc
A 12mm lug torqued to, can't believe it went to 200 lb/ft, but it reaches to 25423 pounds.
Aluminum has a propensity to extrude and creep.
Since these are hemispherical lugs used on the alloy wheels it is possible that the aluminum extrudes and creates a deeper well. Not by much maybe but it may be damaged.
IF it opens the diameter a bit and you now only torque to 80 lb/ft, you are not seating the lugs properly to the wheel.
There is also the possibility that at 200+ there MAY be micro-cracking going on in the alloy wheel at the point of contact with the lugnut.
The lugs probably can withstand the tension applied to the threads but with the higher tension applied, the bolts could be fatigued from the heat/cool cycles of the brakes, etc. This fatigue reduces the shear strength of the bolts too.

Your hypothetical question of 50k-100k miles means the wheels spun around 39,550,000 - 79,100,000 revolutions (I calculated a std 215x55/R17 tires - 791 revolutions per mile)in those hypothetical miles. That's a LOT of shear force being applied on those extremely overtorqued lugs/studs.

Given the clamping force I don't think there is much sheer force on the studs at all.

 

[Miker]

@AlanTheBeastV2 I was more thinking that the clamping force may have stressed the material of the stud and therefore reduced the strength of the stud - possibly allowing the shear strength to be to be compromised.

actually it's lbf/ft (pound-force / foot) for torque. My faux pas.

A foot / pound-force is a linear measure (takes a pound-force to move something linearly for a foot. Measure of work.

But we all know what we mean.

 

[qman]

If you're lug bolts stretched from being over tightened then that would mean they stretch more and more each time. Same thing if you didn't "over"tighten them and only did 80 ft-lb, only they would stretch/stress less. So now that you're gonna do it right and only torque to 80 ft-lb, the bolts will feel a lot less stressed.

 

[AlanTheBeastV2]

@AlanTheBeastV2 I was more thinking that the clamping force may have stressed the material of the stud and therefore reduced the strength of the stud - possibly allowing the shear strength to be to be compromised.

To be sure there is some shear there, so if weakened it would be an issue. 👍

Is it ok to torque wheel lugnuts, that have been overtightened for years, to their lower, recommended torque.. or.. should they be torqued 5-10ft/lbs over, just to be on the safe side?

The only reason I torque my lugnuts at 82.5 Ft-Lbs is that my torque wrench is about 10 years old and I don't get it calibrated. I think in the fall I'll bump that up to 85 Ft-Lbs.

 

[The_K_Man]

If you mean 150 ft-Lbs as the set torque I'd not be esp.
worried for a Honda Accord which 80 Ft-Lbs in pretty
much all cases over the past ... 20 years?

If you mean 150 + 80 = 230 ft-Lbs then I'd replace the
studs and lugnuts.

I do mean 150 ft/lbs: 80 + 70.

So you are saying that lugnuts that might have been over torqued to nearly twice spec(150 as oppsed to 80 ft/lbs), with alloy wheels, during the prior ownership, are ok to be correctly torqued to the spec 80 ft/lbs?

My gut tells me otherwise. If they were consistently overtorqued by 5-10 ft/lbs, then we wouldn’t be having this discussion. But 190% of specified torque?? Whollllle ‘nother ballgame, with all due respect.

I’ll overtorque by a few ft/lbs, just to be safe, thank you very much.

 

[AlanTheBeastV2]

I do mean 150 ft/lbs: 80 + 70.

So you are saying that lugnuts that might have been over torqued to nearly twice spec(150 as oppsed to 80 ft/lbs), with alloy wheels, during the prior ownership, are ok to be correctly torqued to the spec 80 ft/lbs?

My gut tells me otherwise. If they were consistently overtorqued by 5-10 ft/lbs, then we wouldn’t be having this discussion. But 190% of specified torque?? Whollllle ‘nother ballgame, with all due respect.

I’ll overtorque by a few ft/lbs, just to be safe, thank you very much.

As I pointed out above, if really concerned, then rather than arbitrarily deciding a threshold, you should measure the studs for signs of permanent deformation.

No deformation? Fine, torque them to 80 Ft-Lbs as usual. Add a little if you like.

Otherwise, to be safe (if only in your head), replace all of the studs and lugnuts.

But frankly, this is an area where the safety margin is very conservative as mtts60 pointed out.

And stop writing "Ft/Lbs". Sort of indicates you don't even understand what torque is.

 

[The_K_Man]

And stop writing "Ft/Lbs". Sort of indicates
you don't even understand what torque is.

Then what is the common terminology to indicate such spec??…
https://www.discounttiredirect.com/learn/wheel-torque#honda

(I guess discount tire is also using the wrong terminology!)

 

[AlanTheBeastV2]

Then what is the common terminology to indicate such spec??…
https://www.discounttiredirect.com/learn/wheel-torque#honda

(I guess discount tire is also using the wrong terminology!)

Yes. You can see Honda write it correctly: Ft - Lbs. Torque is length times force. (Pedantically LbFt or FtLb, no dash; but certainly no slash "division").

Nm is better, but getting common Americans to the one true faith of metric is not easy. Your government went metric in 1896. 'bout time y'all caught up.

 

[The_K_Man]

Yes. You can see Honda write it correctly: Ft - Lbs.
Torque is length times force. (Pedantically LbFt or
FtLb, no dash; but certainly no slash "division").

There is a technical term for what you are doing, above:

‘Nitpicking’

And it contributes nothing to the conversation. Everyone else here understands what I mean. Plus, I sense that you did not grew up with the learning challenges that I did - explaining why I saw ft - lbs as “ft/lbs”.

Be thankful I don’t pronounce the second month on the calendar as ‘febyooairy”, or as most Yanks do, pronounce nuclear “nu-q-lar” 😆