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Discussion Starter #1
Hi all,

I'm putting on Wilwood rear discs currently and am finding that the shoulder on my original wheel studs protrudes too far through the hub, keeping the rotor from seating correctly on the hub. I need to find some studs that have a narrower shoulder!

What I currently have: 1/2"-20 studs, 0.625" knurl, shoulder length ~9/16", underhead length 1&5/8"
What I need: 1/2"-20 studs, 0.625" knurl, shoulder length 1/2" or less, underhead length somewhere between 1&1/2" and 1&3/4". I think 1&5/8" length would be perfect, 1.5" might be a little short?

I'm having a hard time finding something that fits that bill that I'm confident will work - I know a bunch of people on the forum have rear discs on their cars - what have you all used?

Thanks!
 

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Dorman 610-080. 1/2"-20 thread, .625" knurl, .313" shoulder length, 1-15/16" underhead length which can easily be shortened with a 4.5" angle grinder and a cut-off wheel.
 

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Hi all,

I'm putting on Wilwood rear discs currently and am finding that the shoulder on my original wheel studs protrudes too far through the hub, keeping the rotor from seating correctly on the hub. I need to find some studs that have a narrower shoulder!

What I currently have: 1/2"-20 studs, 0.625" knurl, shoulder length ~9/16", underhead length 1&5/8"
What I need: 1/2"-20 studs, 0.625" knurl, shoulder length 1/2" or less, underhead length somewhere between 1&1/2" and 1&3/4". I think 1&5/8" length would be perfect, 1.5" might be a little short?

I'm having a hard time finding something that fits that bill that I'm confident will work - I know a bunch of people on the forum have rear discs on their cars - what have you all used?

Thanks!
I drilled the rotors to get pass the shoulder.
 

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I used the Summit rear disc brake kit and I seem to remember I had the same issue. I too drilled the rotors.
 

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This is where a friend with a metal lathe comes in real handy.
 

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Discussion Starter #8
I believe I have solved the problem!

I did some more measuring and found that a 1&5/8" stud would actually be too long, even if the rotors were machined to slide over the existing studs. The stock lug nuts are very short with a little less than an inch of thread, the wheels (with lug nuts seated in them) add 0.25" thickness, and the rotors add about 0.2" thickness. When I mocked it up using spacers (washers) equivalent to the thickness of the rotors on the existing studs, I found that the lug nuts were bottoming out before the wheel was tightened all the way. So, good to know.

The solution is then either to hog out the rotor stud holes and buy new lug nuts, or buy a set of 1.5" lug nuts with a <0.4" shoulder. Found that the Dorman 610-126.1 fits the bill perfectly - 1/2"-20 thread, 0.625" knurl, 0.375" shoulder, 1.5" underhead length. A set of ten of them was 20 bucks from Advance Auto. Mocked up with the wheels, they should have about 0.7" of engagement with the lug nuts which is the same as my fronts. Haven't installed all of them yet but I expect no problems. Since I have the rear brakes all blown apart and axles exposed anyways, it's not a whole lot of extra effort on my end to swap them out.

As a tip - installing studs is super easy, even if you don't have an impact wrench, as long as you have a thrust bearing laying around. I have one that I use in my coil spring compressor kit. All you have to do is put the stud in, place the thrust bearing over the threads on the other side, and then get a scrap lug nut threaded on on top of it. You should be able to press the stud in by drawing it through just by tightening the nut, and the bearing makes it super smooth and easy to do because there's no friction between the face of the nut and the hub.
 
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