1/2 wheel studs ???

[rohrt]

My dumb question of the week. My car is a 68 F-bird. Would like to do a C5 brack upgrade in the future.

• When is it advised to changed from the stock 7/16 studs to a 1/2 studs?
• What sanctioned bodies require it and when? (eg drag racing. 11.99 and lower et)
• If required does this usally mean the fronts as well?
• How does this limit your Rim choices?
• I would assume any C5 rotors would need to be drilled out for the larger studs.

[DriverzInc]

I think Tobin at Kore3 could answer most of your brake questions. As for the wheels: Most wheels are drilled to accept a 60* tapered lug nut, most commonly referred to as an acorn lug. If this is the type of wheel you are looking at, the lug diameter will not make a difference unless you are going with something HUGE and overkill like a 5/8s stud. The other type of lug is a drag race shank and washer style lug, like what the WELD Drag lights, or Billet Specialties Street Lites take, which is a totally different story.

I hope some of that information helps. If you need more assistance, feel free to call.

[T/Aaron]

You may want to upgrade to 1/2" studs if you're really going to run it hard at the track. That would be it I think. I upgraded the rears on mine, but I expect to take it to the road course and drag strip, possibly with slicks.

[John Wright]

If you upgrade to 1/2" studs....don't forget that the C5 rotors will need to be drilled to slip over the new studs.
EDIT: whoops, you already were aware of drilling the rotors.
It's not a big deal, I did mine on my drill press at home.

[6'9"Witha69]

I went 1/2 on mine a long time ago when upgrading rear axles. I needed longer studs to pass inspection too, and the Moser rep recommended the 4" long 1/2" studs. No issues with any rims I've ever put on the vehicle.

[Apogee]

I think most people would agree that the original 7/16" studs are adequate for the original tires that came on these cars...beyond that, a wheel stud upgrade is a good idea. Not so much because it's absolutely necessary from a strength stand point, but because of the damage a car can sustain if/when wheel studs fail. Think of it as cheap insurance.

C5 and C6 rotors are typically drilled to ~.53" for the wheel studs since they came with M12 studs [.472"]. We run these rotors on 1/2-20 studs all of the time without any mods, however a quick pass with a 9/16" drill bit will open up the holes another .03" and make assembly/disassembly that much easier. The rotor should be hub-centric, so the wheel stud hole size doesn't have much effect on anything. Most wheels designed for 60 conical lug nuts oversize the clearance hole (.600" to .625") through the wheel to accommodate up to M14 [.551] or 9/16" wheel studs. As Justin pointed out, 5/8" studs are fairly common in certain racing circles, but are basically overkill for most pro-touring builds and add cost or limit selection when it comes to wheels without adding much, if anything, in terms of performance.

Tobin
KORE3

[DionM]

Do you also install the 1/2" studs up front. If so what do I need for a 68 Camaro drum brake hub? Do you drill and tap them for a screw in stud or do you drill them and go with a press in?
Thanks, Dion

[Apogee]

Do you also install the 1/2" studs up front. If so what do I need for a 68 Camaro drum brake hub? Do you drill and tap them for a screw in stud or do you drill them and go with a press in?
Thanks, Dion

Personally, I would drill and tap them for 1/2-20 screw-in studs because I like having the ability to change a stud without a press if I need to (not a fan of pulling in studs with lug nuts...it's hard on the threads). If you prefer press-in type studs, you can do that as well as there really isn't any performance difference one way or the other.

Tobin
KORE3

[dcozzi]

I have Kore3 hubs with the standard small Dorman studs. How can I drill and tap them for 1/2" ARP studs?
Do I need to use a jig of some kind or is this something that can be done accurately with a drill press at home?
I am thinking the latter.

[Apogee]

I have Kore3 hubs with the standard small Dorman studs. How can I drill and tap them for 1/2" ARP studs?
Do I need to use a jig of some kind or is this something that can be done accurately with a drill press at home?
I am thinking the latter.

Dave, it sounds like you have a relatively old set of KORE3 hubs if they don't have the dual 5x4.75 wheel pattern, one of which is already tapped for 1/2-20 screw-in studs. Based on the drawing revision from 2005, it looks like the standard pattern was drilled to .453, not coincidentally the pilot diameter for a 1/2-20 tap. The knurl on the current studs will negate the top few threads, however with a .85" thick flange, that shouldn't negatively impact anything.

So long as you are confident in your ability to tap the hubs perpendicular to the flange, you should be fine. Please let us know if you have any questions.

Tobin
KORE3