Road & Track or Car & Driver magazine recently ran a test of a few aftermarket brake
kits.  In the article they mentioned the drilling or "venting" was there to provide
an escape for pad material.  This is needed more under the repeated hard-braking
found in road racing conditions than in most of the use our vehicles see.

Dana

> I am no expert, but I thought the whole point of cross
> drilling was to dissipate heat.
>
> Thanks,
> Chris

From: Doktor Tim

>>The only good thing drilled rotors will do is shed water
>>
> for better braking
>
>>in the rain. Every hole is less mass to absorb heat, more
>>
> potential for
>
>>stress risers and cracks, and cooler running is just
>>
> speculation.