95carrera

I discovered I have a cracked lug nut. Where is best place to find one?

First time I pulled my wheels today. These things feel like they are plastic, but can't be right? Must be aluminum?

Ed Hughes

They are alloy-any of the usual parts places will have them. FDM, Sunset, Pelican, etc.

That is indicative of someone cranking down way too hard on them, and not torqueing to spec. Why you never trust an unsupervised tire shop to jack your car or mount your wheels.

95carrera

What is the torque spec?

One wheel almost didn't come off. I had to stand on the darn lug wrench to get it to move.

IXLR8

96 lbf.ft. or 130 Nm.

I'll go up in 2 or 3 stages: 1, 3, 5, 2, 4.

justin-in-athens

replace them with steel ones

600RR

Go-to-guy: http://www.boothedesign.com/boltsstudslugs.html

EMBPilot

i got lugs to delete my wheels locks by posting a WTB in the section on RL, you should be able to snag one cheap. i think there are different kinds though.

you have real wheels,
my turbo twist knock offs feel like they are filled with cement

95carrera

Thanks all, a friendly Rennlister is sending me one. This is a great forum BTW.

bart1

I bought some of these from pelican or paragon once and a couple were non concentric. I usually get Porsche ones now.

911PERVY

I went Boothe Stainless steel, fed up with the crap alloy ones

Randall921

I just replaced mine with steel Rennline ones...$40.

pp000830

This is a dry thread value. Make sure your wheel studs are dry with some electrical contact cleaner before using this value. I use a calculated and substantially lower value as I use anti-seize on my wheel studs.

pp000830

Not sure this is a good idea as the steel nuts are much harder and in contact with the wheel may cause a deformation issue on the mating surface.
This is one of the very few areas where I would use and install the OE solution only.

IXLR8

Normally all torques are "dry" unless otherwise specified. A Porsche Technical Bulletin states otherwise. See attached info.

Tell me how you "calculated" the reduced value of torque. I've often looked for that info.

pp000830

I came out of the fastener industry where we provided customers with charts that included dry and lubricated torque values for various sizes, threads, and grades (hardness) of fasteners. The values were validated using a clamp load measuring device called a Skidmore-Wilhelm Bolt Tester where the bolt turning torque required to pull the fastener into its elastic range (clamping range) can be identified. For my car I looked at values on the chart for fasteners with similar diameters to wheel studs in a very high hardness rage - > SAE J429 Grade 8. • 180,000 PSI to 200,000 PSI Tensile Strength and calculated the average reduction in turning torque between a listed dry threaded fastener and one coated with anti-seize from the chart. Having said this

I am not an engineer and I do not recommend to others to do what I do because the failure mode associated with wheel stud/ fastener failures could be catastrophic. For others I say only use the values provided by Porsche for safety reasons.

I noted your attachment where it suggests using some sort of special lube does not require a reduced value. This is inconsistent with what I have come to understand from fastener engineers. A lubed fastener pulled to a dry fastener torque value may be pulled beyond its elastic range and in the case of very hard steel fasteners such as wheel studs the range is quite narrow and I would feel an over torqued fastener could stretch or fail precipitously. It is pure speculation on my part but the reasoning about the lubricant not changing the value may be based on reasoning or testing where the soft metal (aluminum) nut acts as a self-lubricating fastener as the metal is substantially softer than the stud. If this is the reasoning I would feel that the Porsche published torque value for the aluminum nuts would be lower than the steel nuts.
Andy