20" Cast. And they're lighter than 18" forged from what I've read.

 

I think they're spin-cast... better than regular cast, but not as good as forged. Not sure.

 

Are you blind? FWIW..the GT and GXP both have 19's

 

I love the looks of the GT w/ the 19" wheels. The GXP seems abit overdone, plus I don't like the polished finish of the wheels much.

 

I think the poster meant they preferred the look of the 19in GT wheels compared to the GXP wheels.

 

An OEM can't put "track" pads on a street car. I'm fine with that. I know you want to take your car off the showroom floor straight to the race track though.
The ability to disperse heat is not just a function of rotor diameter. Vented rotors, slotted rotors, drilled rotors, curved vanes, straight vanes, thickness of the rotors on a vented rotor etc etc etc. For a rotor of a given mass, there are better ways to make it dissipate heat than make it larger in diameter.

FWIW though, for the same mass, a large diameter solid rotor will be a lot cheaper than a rotor that is vented with curved vanes.
That's a bad assumption. There are plenty of setups out there that will get more airflow with smaller wheels.

 

I agree with your points except the last one.

But you must agree that bigger rotors are sometimes the most economical way to upgrade brakes. Cross drilling has it's problems and vented rotors are climbing up the expensive ladder. Bigger rotors don't suffer as much from heat stress as much as smaller rotors, plain and simple. Brake pad material is another science but I doubt there'd be many happer customers if GM used a softer brake pad. Brake dust does not look good on those sexy Camaro wheels.

Sometimes the best way isn't necessarily the most expensive way. And GM's smallblock is proof of that notion.

 

I certainly agree that larger rotors can be more economical - and "best" from GM's point of view just might be huge rotors look great and they are cheaper (and take less time to design) than a more elaborate brake setup -- but huge rotors are not required to stop a big car - just the most convenient way to do it.

 

And that's certainly the point I'm making!

 

Nope, that's what I was referring to.