Lug nut torque limit?

dolby · 11-25-2009, 03:46 PM

So this afternoon I got around to taking my wheels off to clean the dust out of the them and could not get the lug nuts off with my normal tools. So I grabbed trust snapon torque wrench to see how tight they actually were. Most all of them were breaking at ~230ft/lbs.

I bought the car about 2months and 3800 miles ago and when the dealership found the car it had 19" wheels on it and they said it would be easy to switch out with another M3 with 18" wheels. So basically I know the dealership wrenched the wheels WAY too much.

My question is...Should I be worried about the bolts being over stressed and possibly failing in the future? If so, I would have them all replaced before getting on the track.

Dolby

foosh · 11-25-2009, 03:55 PM

If they really were at 230 ft/lbs., I would be concerned. I'd replace the lugs immediately, and torque them to the proper 88 ft/lbs.

It sounds as if someone went crazy with an impact wrench. I've seen that before, and actually had lugs sheer off on a car I purchased used. Once I drilled 2 frozen ones out, and replaced the lugs, there were no long-term repercussions.

dolby · 11-25-2009, 04:09 PM

Thanks,

They were definitely breaking loose at~230lbs. The first few I just used a 24" torque bar and it took almost all I could give it to loosen them and I am 6'2" 220lbs.

I guess I'll be giving the dealership a call.

Dolby

foosh · 11-25-2009, 04:15 PM

Definitely replace the lugs. At nearly 3 times greater than the torque spec., the threads may be stretched and their structural integrity is suspect.

VictorH · 11-25-2009, 04:19 PM

Aren't you guys talking about two different things? The force to "break them loose" and torque to tighten them are two different things. I've had the same experience with my left front wheel which had been replaced in the NJ port. The lug nuts had no lube and my guess is that they needed at least 200 ft pounds to break loose as well. In fact I split one of my 17 mm 8 point sockets. I lubed the lug nuts and torqued them properly and no problems. My bet is the elastic limit of those lug nuts is pretty high, but having tight lug nuts with some corrosion or no lube which are stuck are not the same as something that was torqued to 300 ft pds with an impact wrench.

Just to clarify since you said it took 230 ft lbs to "break them loose." Did they "break loose" or did they just slowly loosen with a lot of force. If you've ever loosened a flywheel nut that's tightened to 450 ft pounds, it takes a huge breaker bar, but is loosens by just slowly turning, it doesn't just "break" and is suddenly loose. When you loosened your lug nuts did they start loosening at 230 lbs and then slowly decrease to 220 then 210 etc? Or, was it 230 and then suddenly the lugs are "loose." Those are two different things, and with the latter I doubt your lugs are damaged, but for the sake of a few bucks it might be worth replacing if you are concerned.

foosh · 11-25-2009, 04:28 PM

Lug nuts should NEVER have lube applied to the threads. The torque spec. for lugs (88) is for dry tightening. A wet (lubed) torque value is always higher than dry, and that is never prescribed for lug bolts.

Yes, you may be right that break-loose force is never exactly the same as tightening force. However, the difference between 230 and 88 is extreme.

JCtx · 11-25-2009, 04:42 PM

OP, torque one lugbolt to 88 lb/lbs (and yes, NO LUBE) and break it loose. Get the tighten/loosen factor and extrapolate more or less what was the tightening torque of those bolts to break loose at 230 ft/lbs. But as it was already said, it probably was more than twice the spec so I'd definitely replace the lug bolts and make sure they thread nice and smooth on the hub (don't know which threads would give out first). And make sure the discs/wheels are not warped. Good luck.

Kev · 11-25-2009, 04:47 PM

This is what happens what you over-TQ a greased lug nut:

Image courtesy of Rogue Engineering

dolby · 11-25-2009, 04:59 PM

These nuts were not seized since the car still has less than 4000 miles on it.

When loosening the bolts would peak ~230ft/lbs and slowly go down to 120-150 before feeling loose. And I did check the bolts release torque after tightening to spes (88ft/lbs) and they would start to turn at about 80ft/lbs when loosening them.

VictorH · 11-25-2009, 05:40 PM

Mine weren't seized either and my car had 2,500 miles on it (euro delivery) and the lug that was super tight was corroded. The others were just too tight.

Everyone is correct the lugs should not be lubed but I've placed a bit of anti-seize on all my lug nuts for the past 20 years only because I'm not fond of dealing with corroded lug nuts particularly on my cars where the wheels only come off every few years for tires or brakes (not the case with my M3). Dry is "correct" but when you're dealing with shops, including dealers who don't pay attention or care how tight your lug nuts are and combine that with a little corrosion then you have a headache. Take your pick.

major_kusanagi · 11-25-2009, 07:49 PM

check the rotors too. if it's really at 230ft/lbs, they would be all warped. you would feel braking pulsation.

dolby · 11-25-2009, 09:01 PM

Quote:

Originally Posted by major_kusanagi

check the rotors too. if it's really at 230ft/lbs, they would be all warped. you would feel braking pulsation.

No warping....but the bolts seemed to be pretty evenly within (15ft/lbs) torqued by the few that I used torque wrench on and the feel of the torque bar on the rest.

My only problem with replacing them is the fact i am in Jacksonville, FL this week, live in Charlotte and my dealer is in Atlanta. I believe my dealer should replace the bolts, but can get some here in Jax. Not being a metallurgist, I can't really know if I could have a wheel come off. Besides it hasn't happened so far. Could all 5 bolts shear off driving down the road? Any history of this happening? I am sure there are lots of overcranked wheels out there.

Dolby

foosh · 11-25-2009, 09:24 PM

The probability of you having a problem is exceedingly low, but I would replace them at your earliest convenience. Any problems would be more likely to happen with very spirited cornering.

In fact, they all may be fine, but they aren't that expensive to replace, and given that you know they were very over-torqued, you're better off not taking any long-term risk.

bigjae1976 · 11-26-2009, 07:07 PM

I wouldn't worry about it unless the lug bolt won't thread back in.

Let's face it, tech and mechanics don't bust out the torque wrench on your lug nuts. They've got their impact wrenches on full blast and they squeeze the trigger until the socket stops turning. Probably well above 88lb/ft.

KINGLEH · 11-26-2009, 11:30 PM

sounds like a good excuse to get some wheel spacers with new bolts.. It should NOT take that much force to loosen the bolts.... They were defiantly over TQd and are have been compromised... I would not track the car with those bolts and order some wheel spacers as they come with new bolts.. 2 birds with 1 stone!

slicer · 11-27-2009, 06:36 PM

You should never use a torque wrench to break loose bolts. I would recommend recalibrating if you did so. I agree with others who have stated that it may just be some corrosion.

JCtx · 11-27-2009, 07:33 PM

Quote:

Originally Posted by slicer

You should never use a torque wrench to break loose bolts.

Some are designed for that, like the one included on BMW's jack kit. But a regular one, absolutely not indeed.

dolby · 11-27-2009, 10:47 PM

Quote:

Originally Posted by slicer

You should never use a torque wrench to break loose bolts. I would recommend recalibrating if you did so. I agree with others who have stated that it may just be some corrosion.

I used a dial gauge torque wrench which I doubt would ever be hurt by removing bolts. It is designed for well over 300ftlbs.

And there was absolutely no corrosion on the bolts. The care was built on 8/29/09 and had under 4000 miles on it.

Dolby

**ben@tirerack** · 12-01-2009, 10:53 AM

Quote:

Originally Posted by foosh

The probability of you having a problem is exceedingly low, but I would replace them at your earliest convenience. Any problems would be more likely to happen with very spirited cornering.

In fact, they all may be fine, but they aren't that expensive to replace, and given that you know they were very over-torqued, you're better off not taking any long-term risk.

^^This. If you want to drive the car hard, you do not want to be worrying about suspect lug bolts. More likely than not they are OK, but if you're going to have it in the back of your mind, better to kill the worry and replace the lugs.

11-25-2009, 03:46 PM	#1
dolby Second Lieutenant 43 Rep 262 Posts Drives: 2009 e90 M3 Join Date: Oct 2006 Location: Charlotte, NC iTrader: (0)	Lug nut torque limit? So this afternoon I got around to taking my wheels off to clean the dust out of the them and could not get the lug nuts off with my normal tools. So I grabbed trust snapon torque wrench to see how tight they actually were. Most all of them were breaking at ~230ft/lbs. I bought the car about 2months and 3800 miles ago and when the dealership found the car it had 19" wheels on it and they said it would be easy to switch out with another M3 with 18" wheels. So basically I know the dealership wrenched the wheels WAY too much. My question is...Should I be worried about the bolts being over stressed and possibly failing in the future? If so, I would have them all replaced before getting on the track. Dolby __________________ - 1998 E36M3/4 (retired) - 2005 E46 330i ZHP (totaled) - 2007 E90 335i Black/Blk/Alu Trim (retired) - 2009 E90 M3 - Jet Blk on Blk mDCT - 1987 E30 325is - track car conversion in progress
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11-25-2009, 03:55 PM	#2
foosh Major 27 Rep 1,314 Posts Drives: 2008 M3 E93 Join Date: Mar 2009 Location: Annapolis, MD iTrader: (0)	If they really were at 230 ft/lbs., I would be concerned. I'd replace the lugs immediately, and torque them to the proper 88 ft/lbs. It sounds as if someone went crazy with an impact wrench. I've seen that before, and actually had lugs sheer off on a car I purchased used. Once I drilled 2 frozen ones out, and replaced the lugs, there were no long-term repercussions. __________________
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11-25-2009, 04:09 PM	#3
dolby Second Lieutenant 43 Rep 262 Posts Drives: 2009 e90 M3 Join Date: Oct 2006 Location: Charlotte, NC iTrader: (0)	Thanks, They were definitely breaking loose at~230lbs. The first few I just used a 24" torque bar and it took almost all I could give it to loosen them and I am 6'2" 220lbs. I guess I'll be giving the dealership a call. Dolby __________________ - 1998 E36M3/4 (retired) - 2005 E46 330i ZHP (totaled) - 2007 E90 335i Black/Blk/Alu Trim (retired) - 2009 E90 M3 - Jet Blk on Blk mDCT - 1987 E30 325is - track car conversion in progress
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11-25-2009, 04:15 PM	#4
foosh Major 27 Rep 1,314 Posts Drives: 2008 M3 E93 Join Date: Mar 2009 Location: Annapolis, MD iTrader: (0)	Definitely replace the lugs. At nearly 3 times greater than the torque spec., the threads may be stretched and their structural integrity is suspect. __________________
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11-25-2009, 04:19 PM	#5
VictorH Major 433 Rep 1,286 Posts Drives: '09 M3 Join Date: Dec 2007 Location: SC iTrader: (4)	Aren't you guys talking about two different things? The force to "break them loose" and torque to tighten them are two different things. I've had the same experience with my left front wheel which had been replaced in the NJ port. The lug nuts had no lube and my guess is that they needed at least 200 ft pounds to break loose as well. In fact I split one of my 17 mm 8 point sockets. I lubed the lug nuts and torqued them properly and no problems. My bet is the elastic limit of those lug nuts is pretty high, but having tight lug nuts with some corrosion or no lube which are stuck are not the same as something that was torqued to 300 ft pds with an impact wrench. Just to clarify since you said it took 230 ft lbs to "break them loose." Did they "break loose" or did they just slowly loosen with a lot of force. If you've ever loosened a flywheel nut that's tightened to 450 ft pounds, it takes a huge breaker bar, but is loosens by just slowly turning, it doesn't just "break" and is suddenly loose. When you loosened your lug nuts did they start loosening at 230 lbs and then slowly decrease to 220 then 210 etc? Or, was it 230 and then suddenly the lugs are "loose." Those are two different things, and with the latter I doubt your lugs are damaged, but for the sake of a few bucks it might be worth replacing if you are concerned. Last edited by VictorH; 11-25-2009 at 04:29 PM.. Reason: clarify
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11-25-2009, 04:28 PM	#6
foosh Major 27 Rep 1,314 Posts Drives: 2008 M3 E93 Join Date: Mar 2009 Location: Annapolis, MD iTrader: (0)	Lug nuts should NEVER have lube applied to the threads. The torque spec. for lugs (88) is for dry tightening. A wet (lubed) torque value is always higher than dry, and that is never prescribed for lug bolts. Yes, you may be right that break-loose force is never exactly the same as tightening force. However, the difference between 230 and 88 is extreme. __________________
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11-25-2009, 04:42 PM	#7
JCtx Major General 258 Rep 5,012 Posts Drives: No BMW yet Join Date: May 2008 Location: El Paso TX iTrader: (0)	OP, torque one lugbolt to 88 lb/lbs (and yes, NO LUBE) and break it loose. Get the tighten/loosen factor and extrapolate more or less what was the tightening torque of those bolts to break loose at 230 ft/lbs. But as it was already said, it probably was more than twice the spec so I'd definitely replace the lug bolts and make sure they thread nice and smooth on the hub (don't know which threads would give out first). And make sure the discs/wheels are not warped. Good luck.
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11-25-2009, 04:47 PM	#8
Kev Critical Care Anesthesiologist 481 Rep 8,828 Posts Drives: SMB F83 Join Date: Aug 2006 Location: Seattle, WA iTrader: (24) Garage List 2009 Porsche 911 Ca ... [9.50]	This is what happens what you over-TQ a greased lug nut: Image courtesy of Rogue Engineering __________________ kev { divinum est sedate dolorem } "your friendly neighborhood critical care anesthesiologist"
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11-25-2009, 04:59 PM	#9
dolby Second Lieutenant 43 Rep 262 Posts Drives: 2009 e90 M3 Join Date: Oct 2006 Location: Charlotte, NC iTrader: (0)	These nuts were not seized since the car still has less than 4000 miles on it. When loosening the bolts would peak ~230ft/lbs and slowly go down to 120-150 before feeling loose. And I did check the bolts release torque after tightening to spes (88ft/lbs) and they would start to turn at about 80ft/lbs when loosening them. __________________ - 1998 E36M3/4 (retired) - 2005 E46 330i ZHP (totaled) - 2007 E90 335i Black/Blk/Alu Trim (retired) - 2009 E90 M3 - Jet Blk on Blk mDCT - 1987 E30 325is - track car conversion in progress
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11-25-2009, 05:40 PM	#10
VictorH Major 433 Rep 1,286 Posts Drives: '09 M3 Join Date: Dec 2007 Location: SC iTrader: (4)	Mine weren't seized either and my car had 2,500 miles on it (euro delivery) and the lug that was super tight was corroded. The others were just too tight. Everyone is correct the lugs should not be lubed but I've placed a bit of anti-seize on all my lug nuts for the past 20 years only because I'm not fond of dealing with corroded lug nuts particularly on my cars where the wheels only come off every few years for tires or brakes (not the case with my M3). Dry is "correct" but when you're dealing with shops, including dealers who don't pay attention or care how tight your lug nuts are and combine that with a little corrosion then you have a headache. Take your pick.
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11-25-2009, 07:49 PM	#11
major_kusanagi SWARM & COIN 17 Rep 466 Posts Drives: 09 AW/FR/CF E92 M3 Join Date: Jan 2009 Location: SF, CA iTrader: (3)	check the rotors too. if it's really at 230ft/lbs, they would be all warped. you would feel braking pulsation.
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11-25-2009, 09:24 PM	#13
foosh Major 27 Rep 1,314 Posts Drives: 2008 M3 E93 Join Date: Mar 2009 Location: Annapolis, MD iTrader: (0)	The probability of you having a problem is exceedingly low, but I would replace them at your earliest convenience. Any problems would be more likely to happen with very spirited cornering. In fact, they all may be fine, but they aren't that expensive to replace, and given that you know they were very over-torqued, you're better off not taking any long-term risk. __________________
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11-26-2009, 07:07 PM	#14
bigjae1976 Major General 1571 Rep 8,076 Posts Drives: 11 E90 M3 Individual Join Date: Mar 2006 Location: Houston, TX iTrader: (22) Garage List 2004 BMW M3 [4.50] 2011 BMW E90 M3 [5.25] 2013 BMW 328i [5.00]	I wouldn't worry about it unless the lug bolt won't thread back in. Let's face it, tech and mechanics don't bust out the torque wrench on your lug nuts. They've got their impact wrenches on full blast and they squeeze the trigger until the socket stops turning. Probably well above 88lb/ft. __________________ 2018 F30 320iX Melbourne Red 2011 E90 M3 Monte Carlo Blue 2004 E46 M3 Imola Red 2000 E36/7 Z3 Steel Blue
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11-26-2009, 11:30 PM	#15
KINGLEH Major 98 Rep 1,043 Posts Drives: 00 GTR - 09 E92 M Join Date: Apr 2008 Location: Charleston, SC iTrader: (1)	sounds like a good excuse to get some wheel spacers with new bolts.. It should NOT take that much force to loosen the bolts.... They were defiantly over TQd and are have been compromised... I would not track the car with those bolts and order some wheel spacers as they come with new bolts.. 2 birds with 1 stone! __________________
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11-27-2009, 06:36 PM	#16
slicer Major General 2739 Rep 6,734 Posts Drives: 'E46 M3 Race Car, '23 X7 Join Date: Jan 2009 Location: Wisconsin - Instagram - @slicer_m iTrader: (39)	You should never use a torque wrench to break loose bolts. I would recommend recalibrating if you did so. I agree with others who have stated that it may just be some corrosion.
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