Originally Posted by cobra R Thunderbird
X's 2 on what Robert said. I have stock ones on my mustang and KVR drilled ones on my Tbird and they stop just the same..
Would i like to have cross drilled & slotted on my mustang?.. Sure.. But only to match my rear rotors and for looks.. lol
All four rotors shipped to your door for that price is a pretty good deal. I know there are cheaper rotors out there but I was targeting a drill or slot rotor (or both) and factory rotors are not.
Cross drilling provides the fastest heat dissipation thus reducing fade from overheating but is the most prone to warpage and cracking under constant hard braking conditions such as oval racing. They also help to evacuate water in wet conditions.
It also has the advantage of reducing unsprung weight which every racer knows the advantage of. A lot of factory supercars come with cross drilled rotors, most likely for this reason.
Slotting is not as good at dissipating heat but helps clean the pads better allowing them to bite harder into the rotor. Unfortunately that increases heat. They are also less structurally harmful so reduce premature warpage as compared to cross drilling.
A hybrid offers advantages over either alone. There are less holes than with a purely cross drilled rotor so they are more structurally stable and better able to resist warpage. At the same time, they have the advantage of a harder bite and better water and heat dissipation.