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Minimum nut turns for safe use on Fuchs w/spacers?

On one of my rides, I have a rubbing on the inside wheel well due to a chassis stiffening kit. I need to space out the wheel to lower the rear and try and get some more negative camber....what is the minimum number of turns that a lug nut have to be safe and/or legal for DE or AX?

I can always add longer studs but I would like to avoid the labor if I don't have to....or should I just use open top nuts and see if the studs pass the top of the nut when fully tightened?

Old 01-01-2004, 08:10 PM
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Any mod like that, I'd buy open lugnuts and make sure the studs engage all the way through the nut. While there is an engineering answer to the 'how many turns' question, I would not count turns on something your life depends upon.

If you AX and DE much, you will want to change wheels much, so a nice set of open nuts will help you save the stock aluminum jobs.

Cheers, George
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Old 01-01-2004, 09:15 PM
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I think that accepted wisdom is that you can use a 6 or 7mm spacer with standard studs and lug nuts. I use open steel lugnuts with a 7mm spacer and the stud does not wind rignt thru the nut but I have not had any problems over many track days. When I was involved in racing this was standard practice (although longer studs were also common).

The steel lug nut gives you a little more margin as it is much more difficult to strip out the threads compared with aluminium.

If you are thinking of replacing rear studs, it is pretty easy. Once the disc is off, you can pound out the old studs and slide in the new ones just by removing the handbrake adjuster. I just pulled the new studs thru using the steel lug nuts and a breaker bar plus long socket.

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Old 01-02-2004, 02:41 AM
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Z I think the engineering answer is that there is no additional strength once the nut is engaged the thickness of the stud. i.e. if the the stud is 1/2" dia the nut needs to screw on 1/2" for max strength. This assumes the two materials are the samei.e. steel/steel.
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Old 01-02-2004, 05:50 AM
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I have been told 6 complete turns is the minimum to secure any nut like that.
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Old 01-02-2004, 06:01 AM
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There is an engineering standard.
it is generally accepted in US industry that 1 times the root diameter of the thread is sufficient.
Anything in excess of 1x the root diameter of the thread is just extra insurance.
Old 01-02-2004, 07:48 AM
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you need closer to 8 turns but 6 will work
Old 01-02-2004, 09:25 AM
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Quote:
Originally posted by sammyg2
There is an engineering standard.
it is generally accepted in US industry that 1 times the root diameter of the thread is sufficient.
Anything in excess of 1x the root diameter of the thread is just extra insurance.
That's fine for a steel nut on a steel stud, but when you have an aluminum nut on a steel stud, you need more. I wouldn't use anything less than 2 diameters. 2x14mm=28mm. Probably not a coincidence that stock studs protrude by 30mm from the mounting face.
If you use a spacer, use steel nuts.
Old 01-02-2004, 10:55 AM
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I thought aluminum lug nuts were no longer allowed for most DE sanctioning bodies (IE PCA, POC, etc)

I have nuts of steel.
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Old 01-02-2004, 11:03 AM
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there is no way that lug can go on 28mm, thats over an inch man, i just talked to a buddy at the rack he also suggest 6-8 turns, the problem your gonna have is making sure that the spacer doesnt cover the center of the hub, what i mean is if the spacer is to big your hub will no longer be hub centric (center of hub sticking out), and you will get a vibration, the porsche has to have hub centric wheel or you will vibrate, Kevin (speedwheel.net)
Old 01-02-2004, 11:26 AM
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Kevin,

Are you forgetting that the alloy lug nuts are taller than the steel 356 nuts? In addition, there is the spherical portion of the nut that projects below the suface plane of the Fuchs center ... which means that more than an inch of threads are used inside the alloy nuts! Whether it is actually 28 mm ... I haven't measured, but it is AT LEAST AN INCH!!!
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Old 01-02-2004, 11:50 AM
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from when the lug first catches a thread it should be 6-8 turns I prefer 8, this adds up to a 1/2 +-, Kevin
Old 01-02-2004, 11:57 AM
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How many turns before an alloy lug nut bottoms out? I heard around 11-12. If that's the case, I'd want 8 min. I'd go check, but it raining pretty good right now. Had to pull off the job today.
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Old 01-02-2004, 12:46 PM
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Pitch on the lug nut threads is 1.5mm, so 8 turns would give you 12mm engagement, which is nearly 1/2" but not quite.
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Old 01-02-2004, 03:58 PM
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The PO of my brothers car used front 1/4" or 3mm spacers with the original lugnuts. 1/2 of the nuts were stripped internally after removing the spacers in inspecting the nuts. Could of been some garage used an impact wrench. Point is, I wouldn't trust any alloy nut without maximum engagement.

Old 01-02-2004, 04:42 PM
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