They keep tension on the fastener while the friction surface floats to prevent wobble. My OEM (Post TSB) CTS-V front rotors have the same fastener arrangement.


Is there any intention to do something for the rear?

I am way more interested in some kind of floating / vented rotor for the rear since while front rotor cracks are irritating, there are at least 10 solutions in the aftermarket to the front brake issues between BBK's and floating rotors, while RB.com and wilwood are the only makers of a rear kit that helps keep heat out of the bearing and keeps the E-brake.

I tend to agree with this as well.

So like others have said, what's the price on these guys?

I recently purchased a set as well. After many years of cracked stock rotors and dealing with thermal expansion induced coning and the subsequent brake pad taper, these should resolve the issues, for the front at least. I rebuilt the front calipers and installed a fresh set of Cobalt XR2's. Put it all together 2 days before a NASA Time Trial event and they worked great. Turn 2 at Pacific Raceways is a ~65 mph corner just after Turn 1 where I was hitting 144-145 mph. Consistently hit -1.4+ g's braking for Turn 2 and several other corners on the track. The last picture shows the brake at the end of Day 1 (plus 150 street miles to get to the track).
Since Girodisc rotors are made about 10 minutes from my house, I called them up to place the order and schedule a pick up. Mike from Girodisc gave me a shop tour and I was very impressed to see the CNC mills and lathes machining out the hats, hardware, and final cast rotor finishing. Each rotor is hand assembled and turned on a brake lathe and measured for runout. I'm all for supporting local companies especially when the quality of construction is this high. So far, I'm very pleased. I finished with 1st place and fastest lap time of the event on both days and have another two-day time trial coming up to test these rotors. Noticed no coning/pad taper and rotors are just as quiet as the stock single piece rotors.

https://www.s2ki.com/s2000/uploads/g...983_498583.jpg

https://www.s2ki.com/s2000/uploads/g...983_276103.jpg

https://www.s2ki.com/s2000/uploads/g...983_106570.jpg

https://www.s2ki.com/s2000/uploads/g...983_135986.jpg

https://www.s2ki.com/s2000/uploads/g...983_141350.jpg

Excellent info! Thanks. Are those girodisc pad shims by chance or just the XR2 backing plate? Very glad to hear you aren't hearing any extra noise after putting these things through their paces! :thumb up:

XR2 backing plate.

are they directionally veined?
how much are replacement rings?

Prices would be nice to know.

Since we're not vendors we can't give you an accurate price.

That's why I don't feel comfortable responding to the price questions.

Yeah sorry same situation for me. I recommend contacting RedlinedITR if you are interested in picking up a pair.