I recently installed a new set of rear rotors from a fourth gen that are hubcentric, but I noticed that the studs do touch the outside edge of the stud hole. I presume this could lead toward stud failure and plan on opening them up with a step bit. This rear disc set up has been on the car for several years 93-7 z28 but the rotors are most likely metric in terms of the stud holes and studs are moser 0.5".
Any input?
SS

The reason they touch is because the bolt pattern on the donar car was 5 on 4.65" instead of your 5 on 4.75". If the rotor is supported by the hub I don't see why you couldn't open the holes enough to prevent the studs from touching. Not certain it's a problem though

thats the question, is it a problem?

Not a huge deal but I will have to pull the calipers off which are shimmed etc...
thought I recalled reading somewhere this could cause failure due to stress on the stud when the rotor slowed or stopped. Chances are being new 1/2 studs they would never fail, but.
SS

I could see it being a problem if it rocked on the studs. As for being a problem if it's resting against the studs.... I'd think no since the wheel/tire assembly is torqued with the lug nuts sandwiching it all and the rotating mass on launch and braking would be a lot greater force.

http://img.photobucket.com/albums/v61/gort69/DSCN0197.jpg

Is this what you're talking about? I've wondered the same thing.

:eek:Holly #$%^&... Yes, more than I'd like... maybe a spacer of the same thickness with the same OD and ID needed ????Atleast thats what I'd look at doing.
http://img.photobucket.com/albums/v61/gort69/DSCN0197.jpg

Is this what you're talking about? I've wondered the same thing.

I would have the rotors redrilled for the correct pattern. A good machinist can do it.

Is the caliper fully seated onto the rotor? Seems like the caliper can be further into the rotor.

I would have the rotors redrilled for the correct pattern. A good machinist can do it.

Is the caliper fully seated onto the rotor? Seems like the caliper can be further into the rotor.

This is all stock GM stuff from a 93-97 Camaro z28 - calipers, brackets and rotors, and was a bolt-on deal. To be honest, I've checked things a few times and all is well. I think the rotor bolt circle is metric?

Ahh, so this is the famous 4th Gen rear disc set-up? I would suspect the BC is metric. And yes, the rotor is clamped by the wheel and lugnuts.

Ahh, so this is the famous 4th Gen rear disc set-up? .
That is correct, sir!

I wouldn't worry about it. When your wheel is bolted on tight. It's not gonna move.

I would have the rotors redrilled for the correct pattern. A good machinist can do it.

Is the caliper fully seated onto the rotor? Seems like the caliper can be further into the rotor.

I would even go further to locate a stud that has a taller shoulder , so that the shoulder fits snug in the rotor bolt holes, not on the treads.

I'd be looking into if those are really 93-97 4th gen rotors. The bolt pattern on 4th gens and newer Vette's is the same within .002" as our old Chevy's 5 x 4.75". Based on this http://www.discountedwheelwarehouse.com/Chevrolet___Vehicle_Bolt_Pattern_Reference.cfm Chevy does use a 5x4.53 on 2000 and newer Impala but rockauto shows the same front rotors for a '96 Camaro and 2000 Impala. I once did front brakes on each of these cars in the same day and would sware the rotors were the same.

Even if the studs were centered I would be afraid of the rotor shifting with stud holes so much larger than the studs. Maybe the rotors have been drilled for larger studs...

don't worry about it- if it slid on easily and the wheel goes over it easily, then the studs are still straight.
as already said, every Camaro built from 67-02 used the same bolt pattern, but the 82 and newer cars used slightly larger 12mm wheels studs, so the holes are gonna be a little bit bigger than your 7/16" wheel studs. this isn't a big deal- i had C4 Vette rotors that were drilled for 12mm studs on my Nova with 7/16" studs, and whenever i pulled the wheels off the studs were still perfectly centered in the holes just like they were when i put them on. things aint gonna move when the wheel is tightened down.
the rotors you have might be a slightly smaller bolt pattern to fit both rwd Camaros and the newer fwd Impalas.

Well the rear rotors are brembo and came by mistake and were a major hastle to return and were for 93-7 Z28. I didn't post that pic but it pretty much illustrates my concern.

I ended up opening the holes up on one of the rotors thus far since it cooked my cheap step bit. My concern was that contacting on the stud which in this case are 1/2" and touch the outer portion of a few of the holes. From the factory I believe they are punched. If I were running 7/16" studs there would be ample clearance.

The axles were custom so the center of the rotor matches pretty well, in all probably a non issue, probably should of left well enough alone!

SS