cross drilled and slotted rotors

["Mark Jones" <jones164@domain.elided>]

Both Richard Welty and John Katos are correct to point out that slotted
rotors are to evacuate the gas which can form between the pad and the rotor
and not allow full pad contact and reduce braking effectiveness.  Also,
rotors are more prone to cracking if cross drilled.  I just wanted to keep
my previous post brief.

I have driven my GTV6 hard at the track and pushed my brakes to the limits
on many occasions.  The only time I had any problems which MAY have been
caused by excessive gassing was only one time on a brand new set of pads,
first session out.  The next session after bringing them up to temperature
again, they did not behave that way again.  Some racers experience this
'green' fade with new pads.  It's another reason to be careful first time
out on track w/ new pads.  It never happened at all once I started to use
Axxis Metal Masters.

I read somewhere (I'm sorry I don't recall where) that it was P**rsche who
first drilled brake rotors on their race cars.  It WAS to reduce unsprung
weight.  A side benefit was also somewhere for excess gasses to go, if it
was a problem.  But slotted rotors are apparently the better way to go for
evacuating gas.

Sorry to say, neither cross drilled rotors or slotted rotors are probably of
any use on our Alfas.  The cars are not heavy or fast enough for off gassing
to be a real-world issue.  Before anyone gets offended, another way to look
at it is that the stock brake system is more than capable for any situation
we are likely to throw are cars into, even on the track.

If you think they look cool, go ahead and buy 'em.  Just don't expect any
improvement in braking.

Mark Jones,
Chevy Chase, MD

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