Lots of misinformation in this thread. Here are some facts:
- OE drilled rotors are not drilled ... they are cast that way, and have proper testing and analysis done one them. Most aftermarket cross drilled are actually drilled, and as a result a very much weakened product. They WILL crack, not if, but when.
- Cross drilling is not to help cooling. Initially it was to help off gassing in pads. Modern pads do not offgas, so now it mainly for weight savings.
- Solid rotors offer the best heat dissipation ... there is more mass to act as a heat sink, and they offer more surface area for friction (hence better stopping).
- All the teams I race with use solid rotors (as do we). There is a reason. They work better, and don't fail.
- Slotted is far better than drilled, but you still compromise the rotor to some degree. They are usually used to abrade the pads and keep the glazing off. They will reduce your pad life. If you HAVE to have some bling, get slotted, not drilled.
2007 BMW 328Xi Touring, 6 speed