Saturday, April 12, 2008


Remember Sesame Street?? "One of these things is not like the other...."

So last weekend running at Giants stadium I hear a knocking noise towards the end of my run. No biggie, it happens every so often. I pull to the side and wait for a rerun, check my tire pressures and get back in the car. I pull up to the line and Joe Austin finds this next to my car:
I immediately recognize it and without hesitation Joe points me out of line. I pack up and drive home, thinking about what I'm gonna replace all this stuff with. So I splurged and got these:

Studs are ARP's P/N: 100-7717 and you need 4 of them for the whole car. New lug nuts are steel, I've been running Aluminum for 2 yrs now with no problems but I figured it was time for some fresh ones anyway. They are from Pegasus, P/N 3548-005. Supposed to be high strength steel, def heavy, but they are open ended and 19mm w/no locks which make for easy changing.

So here is the failure point on the stud:
Looking at the cross section it is pretty clear the stud began to fail awhile ago. There is oxidation (rust) visible and there are also "rings" which point to a fatigue related failure. These studs have a minimum of about 80 tire changes so it's not hard to think they would fail sooner or later.

So here is a comparison of the ARP and the KYO-EI studs. It looks like ARP worked a little harder to reduce any stress raisers, especially at the failure point on the KYO-EI stud. I'll also have 5-10mm more of thread to use, which I'm happy about.

All better now.

- Jay


Anonymous said...

Jay, I've had some stud issue's in the past and replace them at least every other year. It's that repeated sheer and tension stress that kills them. Also I don't see a lot of antiseize on those. That will minimize some torsion forces when zipping them on and off with your impact gun.

dan said...

jay's impact gun a year ago was his right foot!

lemme add that you have to reduce your torque settings if using antiseize on the studs.