I think it is because many of them are not built right. Unless you are willing to pay top dollar for high quality cross-drilled rotors, the engineering is wrong. The holes they drill ruin the structural integrity of the rotor itself.

Also, (I think) they do not last very long. They are built for racing and are thrown out after ever race. I don't think they can take the heating and cooling of everday driving.

Crossdrilled rotors are primarily one-race application, then tossed. That'* where the fad came from. "They're RACE rotors!". They micro-crack from hole to hole and from hole to edge after heat-cycling. Then they shatter. Ever watch NASCAR?

Most crossdrilled rotors on the market today are just that. CrossDRILLED. Bad news. The only proper way to do it (like OEM corvette and other premium car apps) is to CAST THE BLANKS with the holes in them, then finish machine them.

The drilled holes reduce the braking surface. Think about that. When you see crossdrilled rotors in the right application, they are typically 12" rotors. Why? They have to make them bigger to make up for the surface area they lost from all the damn holes.

Let the ricers have their drilled rotors, and I'll out-brake them every time in my land yacht after I hand them their *** off the line.

I can attest to the reduced braking efficiency. I used to run a set of EBC slotted and dimpled rotors. Although not crossdrilled, the surfaces were dimpled for the same look. There was indeed reduced efficiency when braking. I am now back to a stock set of Bendix rotors with ceramic pads and the difference is night and day. When the time comes for new brakes, I'll stick with the ceramics and most likely a new set of slotted rotors.

Thanks for the info...I wasn't aware that they weren't as structurally sound or as efficient for stopping. I like the idea of cross-drilled rotors for the added ventilation, but it sounds like the ones worth buying aren't really in my price range right now. Slotted rotors, here I come!

i have Baer DecelaRotors that are cross drilled and slotted. have around 21,000 miles on them, so far so good. i like the shorten stopping distance, and they are a direct OE replacement rotor.

ROD

p.*. they have a 3 year warranty against warpage and cracking.

I saw a Grand Prix GXP over the weekend....had some nice and shiny drilled rotors on it. I'm not saying you guys are wrong, you got some good points, but if GM is using it on the GXP'* then some of them must not be that bad.

Surely you can't mean the same GM that put less-than-adequate brakes on the 92-99s and has never admitted the existence of the upper intake failure on L36s, because I trust my dog more than them....

All exaggeration aside, though, just because a car company does it, doesn't mean that it is necessarily well thought out.

Now, concerning the GXP rotors, I admit I haven't inspected them closely. However I'm willing to bet that if in fact they are adequate, that it is because they made them a larger diameter to make up for the loss of surface area (as Bill said).

Exactly. VERY well put, Ryan!

Yes, the GXP brakes are a larger diameter to make up for it, AND I'll bett the holes aren't DRILLED. They're probably cast in the blanks before machining and hardening, much like Corvette rotors.

Don't try for a direct swap. Calipers will be different also.

i searched gmpartsdirect for front rotors on a 96 Bonneville and according to the catalog theyre the same ones used on the 93-02 Camaro/Firebird...that should definetely expand your rotor options, just a thought.