how about drilling custom holes i.e. 5 holes disc into 4 holes disc (with the same PCD)? is it advisable?
It is not advisable. Reason being that the brake rotor is under thermal stress and even the hub of the rotor is one piece with the brake rotor surface, thus the center hub is also under stress.
If you drill a hole on the brake rotor, be it on the hub or on the rotor surface, it disrupts the grains structure of the metal. A cast hole (like the original hub holes) has the grain structure formed around it in an uninterrupted flow.
Drilling holes, be it on the rotor surface or on the hub just introduces weak points in the brake rotor. Depending on how the vehicle is driven and the thermal load it faces.. its taking a huge risk. Personally I feel manually drilling holes on rotor is stupid, as it jeopardizes the integrity of the brake rotor. Likewise, I feel the same about drilling holes on the brake rotor hub..just buy the right brake rotor for your car.
We're talking about the car's braking system, best not to !@#$ around with it.
---------- Post added at 05:48 PM ---------- 6 hour anti-bump limit - Previous post was at 05:30 PM ----------
As an example, the Chevrolet Corvette C6, came from the factory with cross drilled rotors.. and being a sports car.. a lot of owners drive it enthusiastically. The result, a lot of the rotors cracked.
So if a sports car's factory cross drilled rotors also get destroyed..what chance do you think your typical cheaply mass manufactured would have.
