[Mgs] crossed drilled brake rotors

[WSpohn4 at aol.com]

In a message dated 9/20/2007 12:40:20 P.M. Pacific Daylight Time,  
mgbob at juno.com writes:

There is  a firm advertising slotted rotors. These would appear to
have advantage, in  that they could allow the vapors to squirt out the
slots and to allow  dissipation of steam if the rotors and pads were wet.
How do slotted  compare to drilled? 
Could you write more about these  topics?



 
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Both slots and holes are intended to deal with either gases trapped between  
the pad and rotor, or water from the road.
 
Both promote cracking, sooner or later.  Not a big deal on a race car  as you 
are tossing them out and replacing them regularly. This isn't the only  race 
technique that translates poorly to street use, IMO. The use of Teflon  lined 
brake hoses with woven stainless steel outers poses no problems on race  cars 
but can eventually wear through the inner plastic liner from rubbing on the  
woven sheath when used for high mileages on the street.
 
IMHO the only way to improve this aspect of braking, without incurring  
possible failure, is to use grooved discs which have a groove machined into the  
face. This allows water or gas to escape without the potential weakness of  
setting up a stress riser that cracks the disc.  The problem of course, is  that 
the grooves disappear as the rotor wears, so no one makes them that  way.
 
Bill