[Supras] FW: stock brake rotors

[Chris Smyczek]

Nope. Cryo doesnt just harden the steel. Will not fail the same way, and is
not just steel. If properly treated, it transforms austenite into martensite
and promotes migration of fine particulates within the lattice structure
which would never occur through normal quenching. This is not case hardening
or heat treatment alone. End result is a more ductile steel. One time
treatment is permanent. Proper methods will make your rotor last 4x longer,
wrong methods usually shock the piece causing at minimum micro fractures.
You will never achieve the desired results unless it is done correctly.
Chris

-----Original Message-----
From: supras-bounces at supras.com [mailto:supras-bounces at supras.com]On
Behalf Of Jeff Mohler
Sent: Friday, April 11, 2008 9:40 AM
To: Walker, Brian (Rich. Dist)
Cc: Khalid Almufti; Supras at supras.com
Subject: Re: [Supras] stock brake rotors


On Fri, Apr 11, 2008 at 7:04 AM, Walker, Brian (Rich. Dist)
<Brian.Walker2 at vdot.virginia.gov> wrote:
> I'm no expert but honestly, I don't think there is a performance gain
>  from those type of rotors. Of course, with slots and drilling you are
>  increasing surface area slightly, which would mean they can shed a
>  little more heat.
---
Yes, you lose BRAKING surface area.

Nobody has proved that they make rotors cooler.  The goal is pad face
temps, which go UP when you lose rotor surface area.

You're also decreasing contact area for the pad
>  slightly, which would mean a little less braking power (we're talking
>  very small amounts)
>  >From the research I've done, pads nowadays don't release a gas layer
>  like they used to which was the main reason for slotting/drilling, to
>  remove or scrap that layer away. When you have a drilled/slotted piece
>  (provided it's added after manufacturing vs. cast into the piece) you're
>  also adding areas prone to cracking.
---
Drilled rotors crack no matter HOW the holes got there if you get
enough energy into them.  Its how a round piece of metal expands.
Has anyone ever seen any evidence of a rotor casting WITH holes?

No..it doesnt exist.

If you put holes in pizza dough, does it stop splitting as you expand
it on the outside edge?  No..thats how a round rotor expands, and
fails with enough energy thrown at it.


>  for street use, most people use slotted/drilled for street because they
>  look cool. There are some processes out there like cryo treating that
>  are supposed to reduce the possibility of cracking, I've never tried
>  them though.
---
Nope.   Cryo hardenes the rotor, which adds some lifetime to it, but
unless the rotor costs like $130, its not worth the $50 to do it.
It'll still fail the same way..its still steel.

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