[s-cars] 16" Avus wheels and ECS Stage 3

[LL - NY]

As Taka said, tires are the most significant factor on braking distances for
a *single stop.  *The larger rotors will occasionally shorten the stopping
distance consistently (that's key for stating a true improvement) due to
being able to reach maximum tire braking traction sooner due to greater
initial torque. For continous braking duty (such as track work) the larger
rotors more massive heat sink means that the brakes can absorb more kinetic
energy before their temp climbs over what the pads/fluid can handle, thus
their advantage for track work. The fixed calipers do add feel and control
over their sliding brethren, but other than the fact that they tend to be
sized for larger pads, functionally they don't have greater performance (as
in stopping distances) over them. Note BMW seems to have had awfully good
results with sliding calipers.

On Wed, Sep 16, 2009 at 2:49 PM, Jim Gates <jim at gates-home.com> wrote:

> That's one of the points I was trying to understand.  I think tires are the
> biggest factor in stopping distances.  Better brakes can help as the tires
> get better (it's harder to lock up better tires).  Not that locking the
> tires up is the standard for shortest stopping distances...
>
> Jim
>
> -----Original Message-----
> From: joe.pizzimenti at gmail.com [mailto:joe.pizzimenti at gmail.com]
> Sent: Wednesday, September 16, 2009 1:23 PM
> To: Taka Mizutani; s-car-list-bounces at audifans.com; Jim Gates
> Cc: s-car-list at audifans.com
> Subject: Re: [s-cars] 16" Avus wheels and ECS Stage 3
>
> So it doesn't affect the stopping distances unless it does.
>
> Gotcha.
>
> Sent via BlackBerry by AT&T
>
> -----Original Message-----
> From: Taka Mizutani <t44tqtro at gmail.com>
>
> Date: Wed, 16 Sep 2009 14:20:56
> To: Jim Gates<jim at gates-home.com>
> Cc: <s-car-list at audifans.com>
> Subject: Re: [s-cars] 16" Avus wheels and ECS Stage 3
>
>
> It doesn't affect your stopping distances for one stop, except that better
> modulation of the brakes will allow you to brake harder without lockup,
> which will improve stopping distances. For repeated stops or stops from
> very
> high speed, the larger rotor and thus larger heat sink will make a
> difference.
>
> There was a thread recently on corvetteforum about a guy who had brake
> issues even doing one stop from 180mph.
>
> Better tires will make a big difference in stopping distance- just saying
> that you can lock up a crappy set of tires means nothing. I can lock up the
> snow tires on my Miata in the dry pretty easily- that doesn't make the
> stopping distance with those tires any good. Now I can't lock up the
> RE-01Rs
> unless I try really hard. Stopping distances are much better with those
> tires, due to superior traction of the tires.
>
> Taka
>
>
> On Wed, Sep 16, 2009 at 1:44 PM, Jim Gates <jim at gates-home.com> wrote:
>
> > This discussion brings up two things that I've been pondering for a
> while.
> > The torque leverage of a larger rotor and pressure applied to the disc
> > would
> > really only help with brake feel (pedal pressure and modulation) and not
> > actual stopping power, correct?  Larger rotors and pads have a higher
> heat
> > sink capacity and allow more repeated stops without fade.  Also correct?
> >
> > Actual stopping distances will depend almost solely on the tire/road
> > interface based on locking the tires up, right?  Therefore tires
> determine
> > stopping effectiveness in a much larger degree than the size of the
> > brakes...???  So, bigger brakes would be beneficial for the track where
> > large amounts of heat dissipation are required but not necessarily on the
> > street.  If you can lock up your brakes (or activate ABS) you are not
> going
> > to stop any quicker in a normal street braking event with bigger brakes.
> > They may feel better and allow you to apply less pressure to the pedal
> but
> > they don't really allow you to stop any quicker.  Someone explain the
> > physics to me if I'm off.
> >
> > Jim
> >
> >
> > Steve-
> > I don't know- the greater brake torque of the larger rotor would help. I
> > have not researched this stuff any further than circa 2002 or 2003
> because
> > I
> > have not had my 200 since late 2004.
> >
> > I think that larger rear rotors is a waste of money- they don't do that
> > much
> > of the braking as it is.
> >
> > When you say stock caliper, I take that to mean a 993tt caliper with a
> > larger rotor (larger than the 322mm stock rotors, right?).
> >
> > Do you really need that much larger of a brake rotor? I would look at
> > improving traction before doing that unless you're fading Big Reds with
> > race
> > pads and fluid.
> >
> > Taka
> >
> >
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