2012 V Coupe Black Raven, 2011 CTS Premium Coupe Black Raven, 2010 CTS Premium Sedan
I'm just curious but what would cause the rotors to warp in the first place?
HIwhat brake package do you have? Do you have front vent tube for the brakes? do you have staggered tires? how long have you had the car?
warped rotors are normally the culprit, BUT I have had a bad tire or tires cause the same problem.
In my case, I first had the warped rotor cause it. When I took the rotor off to have them reface the rotors are warped so back they could not cut them.
Install New rotors and the problem goes away, ALMOST. It still has a small shimmy only under braking at speeds above 60 PMH. Plus I have a shimmy at 80 MPH with no brake application. I spend months doing balancing at tire dealer and they can not get rid of the 80 MPH vibration in the steering wheel and they blame the high-speed braking on the rotors, not the tires.
I go to another tire shop that has a Road-Force balancer. This machine will find a problem inside the tire or the wheel that has run out. Not just a balance machine. They found a bad tire.
My tire dealer would not help.
this story would go on for months but in the end.
The 60 MPH brake shimmy got worse and the shimmy at 70 MPH plus I got a nail in both front tires so I retired the tires early. Got a set on NEW Continental extremes with road force balance and now NO shimmy under braking at any speed and no high-speed shimmy.
Continental extreme DWS 06 will have a shimmy or thumping first thing in the day and it goes away in a few miles. all of my Conti's do that.
So rotate the tires front to back and see if the brake vibration or shimmy goes away. if it does take a hard look at your tires.
It sounds like the usual warped* rotor issue. Easy enough to check the rotors for runout. Unfortunately, putting new JE5 rotors on is just a temporary fix if you've already discovered the JE5 are inadequate for your purposes. J55 is not an expensive upgrade and may make sense if you need brake work anyway. The wear life and maintenance is much improved with J55.HI
to answer your questions, its the performance coup, I have had the car 6 years, it has different size wheels and tires for the front and rear, so rotation is only side to side, Tires are in good shape, full brakes and rotors were changed at the dealer 20K miles ago. This happens mainly at high speed braking - like getting off the parkway exit ramp. because this is now the 4 time it had happened, Im wondering if its some type of design flaw in the caliper or rotor or combo to cause this vibration?