12:05 Garage- ’70 Duster build

DionR said
I've been looking at wheel studs for my brake kit and was looking at this post for other reasons when it dawned on me that when you said you needed studs with longer shoulders, it was because that was how you centered up your rotor wasn't it. I've been noodling how to get the SP front rotor centered on the hub and hadn't thought of that until I realized that maybe that's what you were talking about.

Is this the stud you used?

ARP 100-7707

I did up some tubes on my 3D printer that fill in the space around the current stud on my hub and it seemed to work well, but not sure if I can get them made without costing an arm and a leg. I also setup a ring that piloted on the bevel on the backside of the rotor, but the best price I found to get that made was almost $200 each for metal 3D printed. Machining was significantly more. Not an option.

I also thought about a 3D printed plate that would pilot on the studs and the holes in the rotor and allow for a couple of nuts to be tightened down to lock the rotor and hub together. It would also have a pilot to use to punch the rotor and then the plate could be removed (leaving the nuts) and the rotor and hub could be match drilled and tapped for a small countersunk screw. Biggest issue with this idea is it would make it harder to replace a rotor if something happened 1000 miles from home. Haven't given up on the idea, but your studs make a lot of sense.

Last question, did the hole pattern in the rotor match the bolt pattern in your hub? Can't tell from the pictures for sure. Being that it is an LX/LC rotor, in theory there should be some misalignment. Weird thing is, on my OEM JY rotor, it is definitely a 4.5"/114.3mm bolt pattern in the rotor. Five concentric tubes fit over the studs and the rotor slips on and off easily. Hard to believe they would do that if the hole pattern was 115mm. I wouldn't be surprised if the aftermarket rotors for an LX/LC are actually 5x115mm and the hole in the rotor large enough to fir over the studs, but it appears this OEM rotor from an '06 Magnum SRT-8 had a 5x4.5" bolt pattern.

Yes, the longer shoulder on the studs is what centers the rotor on the hub. I don't recall the part number studs I used, but those look like them. The lug holes in the rotors are quite large. I want to say they are around 5/8". This is another reason I wanted the shoulder because the rotor would have been able to move on the threaded portion of the 1/2" stud. The .0275" difference in the bolt pattern is easily overcome by large holes in the rotor. What I should have done is had the center of the hub turned down to match the center hole of the rotor. I don't recall the size difference but it wasn't much. I just opened it up with a die grinder and sent it. I didn't put a dial indicator on the outside of the rotor, but I did spin in it while closely watching the clearance to the caliper. My eyeball measurement showed zero runout and I have no vibration.
I think you may be overthinking it (not a bad thing). If I were to do it again, I'd turn the OD of the hub down a touch so the rotor fit perfectly. Other than that, it's quite easy. If I remember correctly, the Mustang rotor center hole was a bit smaller also.
I did consider drilling and tapping the rotor/hub to hold the rotor on, but it didn't seem necessary after everything was fit up. The brake pads pretty much hold the rotor in place when the wheel is off.