Are my rotors bad?
 

For about month now , the rx-8 will start shaking when I press the brakes hard when I am going over 80mph. The shaking happens in the front, I am guessing its the rotors. Will this be covered under warranty?

depends on how many months you've had it I guess..

rotors are like clutches and brake pads, they are made to wear out. If you sit with your brakes on after a lot of hard stops, or parking brake, you can cause the rotors to warp.

Good call.

Rotors fall under Mazda's "adjustment" period.

12 months or 12k miles.

I wouldn't say anything about 80 mph when you talk to them, just say "when slowing down from highway speeds"

They put new rotors on mine AFTER 14 months - rust and warpage to the n'th degree

Thanks for the info, the rx-8 is about 18 months. If I take it the dealer will they charge to diagnosis the problem. Do you guys think it could be something other than the rotor?

classic brake rotor symptoms, I think they should be covered under warranty since it's an unusual amount of wear on those components.

Tires.

He didn't mention any issues even at 80 mph until he hit the brakes... why would you say tires?