anyone running solid rotors

 

Are you asking about true solid rotors?

Regarding brakes in general, I have been thinking of changing my brake setup too. Would really like to increase my cars braking performance. And, since my stock rotors are developing quite a few cracks between the holes that are growing and need to be dealt with soon, I thought that it would be a good time to make some changes.

In one of the many magazines I read recently, I saw an ad for a rotor that had round "divots" (not holes) in them, that looked inetersting. My suspect memory also recalls, seeing slotted rotors that did not penatrate as well. And, I seem to recall that several Porsche race teams are using setups with PFB rotors and Alcon calipers. Does that sound right? Looks like there are quite a few possible setups to choose from.

So, I'd also be interested in hearing from anyone with experience in this area. Oh ... anyone tried cryogenic treatments on their rotors, calipers etc. yet?

 

As to cryonic treatment, I would happily argue the physics. I
have a degree in engineering and material science, and have
subsequently interrogated some of the best metalurgists
in the world, and the consensus is that cryonic treatment is
hooey. Just like companies still sell teflon oil additives after it
has been shown they don't work, there is no economic incentive
to loadly declaim additives or cryonic exorcism, but there is
big incentive to sell them...
If there are any published independent blind tests of
cryonic treated rotors, I would like to see them. My research was
a while ago.
Joe
Joe

 

Joe, I take it that you are saying that there is absolutely no change in the structure of the metal after being cryogenically treated? It seems to me that I read something a while back that showed the "grain" structure being affected by this process. And that it had been used by manufacturers of products unrelated to the auto industry, as a stress relieving process as an alternative to annealing and other heat related processes. The anecdotal evidence seems good. But, it is published by those who stand to profit. I agree, it is hard to argue science.

 

Hi Bob, yes I am saying that cryonic treatment has no effect on
the crystaline structure of the metal.
As it cools from a molten state, iron goes through some
phases, and depending on the amounts of impurities in the
metal, there are two main crystaline forms that happen. However,
The main physical characteristic that determinse the structural
behavior of the metal is that it is multi-crystaline. If we could
construct a mono-crystaline part it would be 100's of times
stronger than we find in real pieces.
The main failure path in metal is along the boundaries between
adjacent crystals. These are 1-2 atom-wide gaps where atoms
are trapped in a less-than-ideal state. Thse gaps are formed
because when metal cools past the incipient crystalization
temperature, crystals start spontaneously in many places
according to wherever the part is coolest. These crystals grow
independently until they (very quickly) bump into adjacent ones.
The as-yet-crystalized metal in between the crystals is co-opted
into one side or other, but because these crystals are irregularly
shaped and are oriented in different directions, they end up
frozen together in a random order with ill-fitting boundaries that
have up-to-atomic-sized gaps between them.
This crystalization occurs at red-hot temperatures. Now, for
cryonic treatment, the freezing *removes* thermal energy from
the part. There is no energy or mechanism for re-orienting those
irregular crystals, or for making them magically into more regular
shapes that would magically all fit together like a jigsaw puzzle.
They are in effect promising that if you were to fill a box with
irregularly shaped ice cubes, and freeze it reeally cold, that all
those cubes would suddenly swap bits of ice to become the same
size and also move around till they were neatly stacked.
Secondly, for any part like a rotor that gets very hot on a
continual basis, the part is re-crystalizing every day. Even if
cryonic exorcism did anything, it'd be like drawing on the beach
at low tide. It'd last until you did your next downhill stop.
Joe

 

Well ... it looks like science and common sense seem to agree on this one, doesn't it. I had thought about the heat cycling aspect these parts go through and wondered that if the cryogenic treatment really did something that the heat would likely undo it. Thanks for the explanation Joe.