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      12-11-2010, 04:15 PM   #1
LiM3y
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Replacing lug nuts - fatigue?

I was tooling around the internet, like you do, and I was looking at wheel stud conversion kits on the EAS website. They note that the studs should be replaced every season.

Does anyone here replace their track lug nuts on a regular basis? Is this something one should be doing? I hadn't even thought about it until I read the comment on the website.
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      12-11-2010, 04:48 PM   #2
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Funny you should ask. I was just switching out my summer to winter wheels and one of the lug nuts literally disintegrated while taking it out. I imagine this is due to fatigue from about 8 track days in the past 8 months. So yes, probably wise to replace them all every season. You can get them at your local auto parts store from about $3.
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      12-12-2010, 12:05 AM   #3
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Quote:
Originally Posted by R A W L S View Post
Funny you should ask. I was just switching out my summer to winter wheels and one of the lug nuts literally disintegrated while taking it out. I imagine this is due to fatigue from about 8 track days in the past 8 months. So yes, probably wise to replace them all every season. You can get them at your local auto parts store from about $3.
It was either defective or had been seriously over-tightened. You should replace all of them as soon as possible.

If they're not over-itghtened, they'll last for years.
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      12-12-2010, 05:06 AM   #4
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^agreed. It would be very un-German to design lug nuts that would fail after a year (even with track days).

I have buddy with a 2007 Z4M. Advanced solo driver. Uses slick tires. 4 years and at least half a dozen track days per year... still using the same lug nuts.

That said, I would replace them out of precaution every couple of years... if you track often that is. If you only drive on the street the lug nuts will probably outlast the life of your car.
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      12-12-2010, 09:11 AM   #5
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I have been very careful to NOT over-tighten my lugs by using a measurable torque wrench (88lbs), so that's probably not why the lug nut fell apart. I think my failed lug nut was due to both some degree of fatigue and some degree of defectiveness. All things, even german/BMW made, have the potential for defectiveness and fatigue from hard use. EAS is recommending replacing lug nuts on a regular basis (as mentioned by the OP) for a reason. I imagine they've seen fatigue cause failure and they are advising their clients on how to avoid potential catastrophes for a few bucks - the lug nuts cost around $3. No one is saying that without doubt every lug nut will fail every year. They are essentially saying there is some risk of a lug nut failing, whatever the risk is. And they are offering precautionary advise to lessen that risk.

Now to be clear, I think this advise should be taken most seriously by those who track a lot. And by "track a lot" I mean at least once a month being on an open, high speed track for 5 - 30 minute sessions a day. This means high-speed, heavy breaking, hot brakes, hot wheels with signifiant loads being transferred to them from all angles repeatedly, and then relatively fast cool down processes - all these equal potential for fatigue. Street driving and even repetitive advanced solo/autox driving is not as evasive and hard on equipment as extended high speed track driving, IMO.

Last edited by R A W L S; 12-12-2010 at 09:31 AM.
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      12-12-2010, 07:21 PM   #6
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Are we talking about "LUG BOLTS" ? ....or "STUD & NUTS" ?

- Lug Bolts should be replaced every couple of years if you track (change wheels) at every track event and you track often (once a month).
The idea is that the heads of the lug bolts fatigue from constant torquing and re-torqing

- Studs & Nuts, if they are quality product (like ARP) ....then you should not need to replace them for longer (if ever at all) ...since the only fatigue/wear is on the threads of the stud.
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      12-12-2010, 08:43 PM   #7
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Quote:
Originally Posted by mastek View Post
Are we talking about "LUG BOLTS" ? ....or "STUD & NUTS" ?

- Lug Bolts should be replaced every couple of years if you track (change wheels) at every track event and you track often (once a month).
The idea is that the heads of the lug bolts fatigue from constant torquing and re-torqing

- Studs & Nuts, if they are quality product (like ARP) ....then you should not need to replace them for longer (if ever at all) ...since the only fatigue/wear is on the threads of the stud.
The comment was for studs...after reading about stud conversion kits at a vendor site. Your comment above contradicts the advice on the website.

I was wondering about lug bolts subsequently.
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      12-13-2010, 06:49 AM   #8
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Check your threads, the BMW OEM bolts are very strong. I replaced four or five over three years with my 335i over 40+ track days. Never had a failure and thread damage was due to me being careless with my impact wrench. Just make sure you torque to specs.

Oh, and I'd recommend you stick with OEM. Very cheap from the dealer with BMWCAA.
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      12-13-2010, 06:31 PM   #9
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Next, if you're tracking with lug nuts, please don't use aluminum lug nuts and use some nice quality steel ones.
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