Exploding Rotors: why you do not drill

[Duncan Thomson]

I'm with Fred and Bob on this one, cross-drilled rotors should most definitely have a symmetrical
hole layout.

> In any case.  This is what I'm typically used to seeing with regard to
> drilled rotors (http://home.attbi.com/~jbipes/ttr/frntrotors.html).  Scroll
> down the series of photos on the left side frame and there are a few of
> Zimmerman x-drilled TT rotors.  Simple symmetrical spiral pattern.

these are how they should be done... the rough approximations must be home-builts, and appear to
have been done without even the aid of a decent drilling jig...

> found this site (http://www.evoms.com/vw%20brake%20page.htm) that shows what
> appears to be the same irregular pattern as that on the failed rotor (Look
> at the Level 3 brakes).  So, it seems I have to recant my comment about it
> being a home made hack job.  I guess it's a factory hack job ;-)

nope, not a factory hack... these are apparently a Porsche caliper, but the rotor has once again
been post-drilled, by monkey with a drill press (IMO)... I wonder if they're even square to the
surface...?

I have to agree with Fred that they are Zimmermann's that have been cross drilled...
and I would challenge anyone to find pictures from a reputable site or brand with discs which have
been drilled in anything other than a symmetrical fashion...

other question is whether the ventilating vanes have been damage in the course of the drilling...

I would consider cross-drilled rotors myself (don't believe they are dangerous as a concept) but
only if I had a good reason to... and they would have to be professionally done....

JM2C
Duncan