GTIR-LOZ said:
i work for mercs and you only see them on sports pack vehicles (prob for looks) and amgs if you look closely at the drill holes they almost all have small cracks forming from them (unless they are new obviously) and the brakes are a hell of a lot thicker than your standard wilwood discs so can prob put up for it for a while
Sorry but, that's not true... You see the crossed drilled disks on the heavier and more powerful Mercs, not just the ones with 'sports packs' or the AMG models. There are S class models parked outside my office everyday and they have cross drilled disks, so did the CL600 I saw yesterday. I've also seen many C class Elegance and Avanguard models with them fitted !
As so do Porsche's, S and RS versions of the Audi's....
Crossed drilled disk cracking (as in proper cracks, that go across the radius of a disk) is a thing of the past. I've had them on my last 4 cars and never once had any cracks appear. My current set of disks is around 10k miles old and they have no cracks !
If you look at un-drilled and un'grooved disks, that have been used extensively, you'll always see surface cracks. It's a result of the metal used to make them and the heat cycling !
The key to cross drilling is not just drill a hole but, shamfer the edge too. And as you said, it also helps if the disks have sufficient thickness to support the cross drilling !
Paul