Warn them what.... 99% of race & serious track cars rip off the cast holes stuff & use grooved Alcons or AP s anyway, tho not so much the track 964 & 993s as they are lighter then Gt3/2 but they do need drilling out after each track day. or as you posted a pic of ceramics they wre such a rip roaring sucess that the owners really swore by them, couple of track days & a 27k replacement cost for discs & pads all round, fantastic kit........ the 2nd generation of ceramics are ment to be a lot better, & replacements are at least cheaper now, but most do just put them in a box for resale & stick steels on there, tho the Carerra Gt owners are a bit stuffed as no steel replacement off the shelf- not many are tracked hard tho, however i do know a fella who tracks pork a lot & is just about to get one so will be interesting to see how they fare.
I can't comment on Porshe's as I'm not a Porsche anorak. The general point I was trying to make is that there is nothing inherently wrong with drilled discs. In my experience the reason for high levels of cracking around/between the holes is due to insufficient radiusing, localized overheating during drilling, poor quality steel or pushing the brake material above a safe working temperature. My feeling is that a lot of the time drilled disc failure is due to the driver being able to raise the disc temperature above what is safe for the material without the self limiting factor of brake fade. My original point was simply that just because Zimmerman discs suck, not all drilled discs are death traps.
But as the topic was asking about Zimmerman discs, it would be fair to assume that the replies saying not to use them because they crack is a fair and valid point. If somebody said "Are cast disks with holes in used by Porsche any good?" and i replied 'No Zimmerman disks are crap and fall apart so you will die!' I'm your rant would be more appropraite...
Golden - you're right it was a sweeping statement. To clarify - I won't ever put drilled zimmerman front discs on a car again. However, I'll quite happily keep using Porsche ceramic drilled discs on my car. (I don't worry about having to re-drill out the holes after each track day as I have a man to do that)
