[Supras] FW: stock brake rotors

[Jeff Mohler]

Chris:

I understand all of that..but the fact is, a rotor is an abrasive
substance in the act of braking.

Ive seen up to 2x longer, and in some rare cases, 3x longer, but
mostly in the 200% range with the customer I work with.

The story is told in the cryo -vs- non-cryo purchase patterns.  The
pad purchases are still once every other month..but the rotor
purchases go down to just under 50% of normal frequency.


But to a very large point..its still the same rotor, and WILL still
fail in a drilled application the same way if loaded up with enough
energy.

On Fri, Apr 11, 2008 at 12:13 PM, Chris Smyczek <csmyczek at molbiores.com> wrote:
>
>
>
>  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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