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cross drilled rotors Scott Williams is WRONG!



Don't forget that a larger disk moves the swept area further from the center
of the wheel and increases leverage on the rotor.  Kinda like adding a pipe
to the end of a wrench for more leverage.

The extra leverage usually isn't needed to help stop the car but can make
the modulation of the brakes easier.


----- Original Message -----
From: "Aireq" <trance_whore@yahoo.com>
To: "Scirocco Mailing List" <scirocco-l@scirocco.org>
Sent: Saturday, March 23, 2002 1:36 PM
Subject: RE: cross drilled rotors Scott Williams is WRONG!


> F = uNA
>
>
> Force of friction is equal to the coefficient of friction, times the
normal
> force, times the surface area. Bigger breaks will stop faster. Simple
> physics. But the question is where the trade off goes the wrong way in
terms
> of weight added vs stoping power.
>
>
> aireq
>
> -----Original Message-----
> From: scirocco-l-admin@scirocco.org
> [mailto:scirocco-l-admin@scirocco.org]On Behalf Of ATS - Patrick Bureau
> Sent: Saturday, March 23, 2002 10:47 AM
> To: Brett Van Sprewenburg; scirocco-l@scirocco.org
> Subject: RE: cross drilled rotors Scott Williams is WRONG!
>
>
> Bret I would agree for road vehuicules and daily drivers, coudl you
explain
> why then F1 Racing and Nascar Use Cross drilled rotors if indeed it
provide
> "now-adays" no evidance of added performance.
>
> inquiring mind would like to know.
>
> ATS - Patrick
>
> =>-----Original Message-----
> =>From: scirocco-l-admin@scirocco.org
> =>[mailto:scirocco-l-admin@scirocco.org]On Behalf Of Brett Van Sprewenburg
> =>Sent: Saturday, March 23, 2002 12:12 PM
> =>To: scirocco-l@scirocco.org
> =>Subject: RE: cross drilled rotors Scott Williams is WRONG!
> =>
> =>
> =>>Hehehe that got your attention ;-)
> =>>
> =>>I don't know about performance, I think everyone is missing the point.
> =>>Rotors have holes drilled into them in order to increase air flow,
> =>>thereby reducing heat in hard driving conditions (such as racing on a
> =>>track). That's the theory behind that. I would say (not from experience
> =>>since my car isn't done) that they would work...It just makes sense.
> =>>Will this increase performance? I don't know, but I do know they would
> =>>have to be cooler (temp) no? Of course it could take a couple of
seconds
> =>>for the pad to grab the cooler rotors (so I've heard). That's why you
> =>>would want to get the braided lines to get a better bite in the
> =>>caliper...As far as Scott being wrong, I think I have a better chance
on
> =>>finishing my car today than proving him wrong...
> =>>
> =>
> =>I really need to post that brake article... :)
> =>
> =>Anyway,  I'm afraid the above opinion is incorrect.  I'll paraphrase
from
> =>the GRM brake article again...
> =>
> =>Crossdrilling your rotors does nothing in most situations
> =>now-a-days,  except
> =>look cool...so please don't say it's for higher performance. (And
> =>they do look cool) ;)
> =>
> =>Rotors were first drilled because early brake pads from the 40's
> =>and 50's gave
> =>off gases when heated to racing temperatures.  The gasses then
> =>formed a thin
> =>layer between the brake pad face and the rotor, acting as a lubricant
and
> =>lowering the coefficient of friction.  The holes were implimented
> =>to give those
> =>gasses someplace to go.  Todays friction materials generally do
> =>not exhibit
> =>the same gassing out as the early pads.
> =>
> =>The holes have carried over more as a design feature than a
> =>performance one.
> =>Contrary to popular belief, they don't lower temperatures.  In fact,
> =>by removing
> =>weight from the rotor, they can actually cause temperatures to
> =>increase a little.
> =>These holes create stress risers that allow the rotor to crack
> =>sooner, and make a
> =>mess of brake pads - sort of like a cheese grater rubbing against
> =>them at every
> =>stop.  Need more evidence?  Look at NASCAR or F1.  You would think
> =>that if drilling
> =>holes in the rotor was the hot ticket, these teams would be doing it.
> =>
> =>Ok, let's debunk the bigger rotors = better here also (again).
> =>
> =>Bigger rotors will make your friends think you are cool, bigger
> =>rotors look sexy, but
> =>bigger rotors do not stop the car.  What a bigger rotor will do is
> =>lower the overall
> =>operating temperature of the brakes - which is a GREAT idea IF your
> =>temperatures
> =>are causing problems with other parts of the braking system. (It can
> =>also changes how
> =>the brakes are modulated by the operator, which might be better
> =>for them).  The
> =>quick motto is bigger is better until your temperatures are under
> =>control.  AFter that
> =>point, you are doing more harm than good due to the load of steel
> =>hanging on the
> =>wheel that needs to accelerate each time the gas pedal is pushed.
> =>
> =>Finally, SS brake lines only remove compliance from the braking
> =>system, which really
> =>affects only the pressures and forces applied, not so much how cool
> =>the rotor is
> =>running...
> =>
> =>Again, this is an excerpt from a rather extensive braking article
> =>from Grassroots Motorsports,
> =>written by an anti-lock braking systems engineer with the Robert
> =>Bosch Corporation who
> =>is a Saturn racer for scR motorsports.
> =>
> =>In my opinion, this probably doesn't matter to the most of us
> =>anyway...very few of us
> =>are pushing are cars hard enough to get into the perfomance areas
> =>where these kinds
> =>of details actually make a difference very often.
> =>
> =>==Brett
> =>
> => \/  '84 Scirocco (ITB racer 2B) | "Hot VW's, take two home.
> =>They're small"
> =>\/\/ '88 Scirocco 16v (Show), '92 Passat 16v (Winter+) | -
> =>brett@netacc.net
> =>
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