|
Tom from Core4 here....
I just want to point out that the sole purpose for moving to a higher class/grade stud is to generate a higher clamping force/preload/tension (how tightly the stud squeezes the wheel-spacer-rotor-hub joint together) to prevent "joint separation" from occurring; which is the death knell of fasteners.
Higher clamping force requires a higher tightening torque yet many people don't take advantage of that enough. It's a concept that's often misunderstood. So if you move to a class 12.9 M14 stud, take advantage of it and bump up your tightening torque!
As mentioned earlier, I use custom spec'd MSI studs on our hubs and also use ARP studs for M12 applications. MSI studs and lug nuts are made in North Carolina and are actually beyond class 12.9 strength specifications.
They also have a high performance/motorsports grade dry lubricant coating on them to prevent exactly what you experienced with your Apex studs. Their lug nuts are coated with the same stuff and using them together ensures more preload, more consistently when tightening (the coating does eventually wear off with use).
Of course ARP is ARP (made in California), but they don't make screw-in type wheel studs so no surprise they're never mentioned in these circles. Their manufacturing process is better (cold working/forging, in-house heat-treating) than MSI's, but catered toward making huge batches (10,000+ per run). MSI's coating is better than ARP's standard cadmium plating though.
As for my tech article, yes, for track cars I do recommend putting a small amount of lubricant (anti-sieze works well) on either the cone seat of the lug nut, or the seat of the wheel IF using a standard lug nut (zinc plated/basic plating) in an aluminum wheel that doesn't have steel inserts (almost all wheels these days). A little goes a long way.
There's also lug nuts out there that have a free floating collar/cone-washer on them from Project Mu, Project Kics, RAYS, and Muteki that I've tested and they are fantastic. No lubrication since they do away with the cone seat geometry wedging effects. They are pricey and not made in the USA, but on my test setup they were the best in doing the job they're supposed to do; preloading the stud sufficiently and consistently. It's why Porsche uses the same design idea with their wheel bolts.
|