I have a 2012 grand sport convertible does anybody cut cross drilled rotors in the Chicagoland area

 

I paid less than $250 for all 4 AC Delco rotors from rock auto shipped to my door a while back. Easier than trying to find someone to properly resurface the old ones

 

Just call around, since should only be about $5 more a rotor to turn the drilled rotors ($60 for all 4).

In my area, (Denver), the Oreillys down the street turns them, since I taught them how to do them them when I needed my done there first turning, and they have done others for lads that have come over to work on their cars at the house as well.

Hence just need to make sure that you have the dampening belt installed on the rotor so you don't get harmonic chatter problems on the cuts, and will take a few light passes (instead of one heaver pass) to turn them (the extra pass the reason for the extra $5 per rotor (over the $10 per rotor they charge for no drilled rotors).


As for the C6 drilled steel rotors, only enough meat on the rotors to turn them once, so you only going to get two sets of pads out of them before the will be too thin to turn another time, including the pad wears to the rotors.

On the ZR1 carbon rotors, can not be turned, so your dropping close to $1K per rotor every time you need to address those rotors.

 

Would you agree that turning rotors is really a short term fix since the thinner rotors will quickly warp due to the thinner metal left on the rotor is less able to dissipate heat?

Tom

 

No, since iron rotors have there minimums before they would be too thin to turn or use even for road course use, and the stock rotors have plenty of meat on them until they get to that point that they would be too thin. Granted that new and min's on the C6 rotors is not a great as some of the older cars that where way over there mins to start, there is still enough meat on them to turn them once after the first set of pads, and still be well over the min's.

Now on the other hand, if the rotors have hot spots on them, then it's time to replace them, since no amount of surface turning removal is going to remove the hot spot difference of the hardened iron spots itself to make them grab uniformly. Hence iron hot harden spots will always be more slick than the other none hardened surface, so even with then turned, your always going to have less pad grab on the harden hot spot areas.


So again, tech turning the rotors will take a good look at them to make sure they don't have hot spots,break out the micrometer to gauge the thickness of the rotors/what needs to be removed to clean them up, and if they are able to turn them and still be above the mins, they are fine to be tuned. Hence turning passes are only a few thousands of an inch, and it not they are reducing the rotor thickness by a half inch or more instead.

To add, in regard to two piece rotors and road course racing, it's not the outer iron rotor part above mins that I worry about, but the inner hat instead. Hence inner hat is made to flex to reduce pad kick out in the corner, and since its the part that is really doing all the flexing and going through heat cycles as well, its the part that will come apart long before the iron rotor do.
At one time, used to reuse the inner hats with new outer rotor when they did get below mins to try to save some money, but having having enough re-used inner hat crack apart from the corning flex fatigue , just buy complete new rotors with new hats once the rotor can not be turned any more and still be above the minimums.