[s-cars] G60 brakes

Mon Oct 27 11:53:06 EST 2003

wait a minute.  the pistons in the BR caliper are set in an opposing
configuration, with two pairs of pistons opposing each other.  that
means you should be taking the effective area of one side, not both
sides.  that means you take the effective area of a 44mm piston and a
36mm piston together.

-teddy

--- Steve Marinello <smarinello at charter.net> wrote:
> Rich:
>
> Actually, I was confused.  That's what happens coming into a thread in the
> middle.
>
> I was confused about the G60/BR piston sizes and wasn't on the same page
> anyway, just looking at the effective single piston equivalent of the G60's,
> but thinking/reading that they were 44 mm + 36 mm pistons, not the two 45 mm
> pistons.
>
> By my way of looking at things, two 45 mm pistons equate to a single piston
> cross-sectional area equivalent to a 63.64 mm single piston, using the old
> pi*D squared/4 equation, adding the two and taking the square root.
>
> By the same method, I get a single piston equivalent of 80.40 mm for the
> BR's, taking the area of two 44 mm pistons and two 36 mm pistons all summed,
> which yields exactly your 26% cross sectional area improvement.
>
> Sorry I was a page back, and being dense.
>
> Steve
>
>
> ----- Original Message -----
> From: "Richard Tanimura" <richard at tanimuras.com>
> To: "Steve Marinello" <smarinello at charter.net>
> Sent: Monday, October 27, 2003 12:19 PM
> Subject: RE: [s-cars] G60 brakes
>
>
> > Steve,
> >
> > I may be way outta synch with everybody here.
> >
> > G60 : 2 pistons/caliper, 45 mm each according to the data given on the
> site
> > I quoted.
> >
> > Big Reds: 4 pistons/caliper, 2 x 44mm and 2 x 36 mm. This is the equiv. of
> 2
> > x 56.8mm pistons. The math is:
> > SQRT( 44x44 + 36x36) = 56.8
> >
> > 56.8/45 = 1.26
> >
> > Rich
> >
> > -----Original Message-----
> > From: s-car-list-admin at audifans.com
> > [mailto:s-car-list-admin at audifans.com]On Behalf Of Steve Marinello
> > Sent: den 27 oktober 2003 16:01
> > To: Richard Tanimura; Keith Maddock; s-car-list at audifans.com
> > Subject: Re: [s-cars] G60 brakes
> >
> >
> > Huh??  back at you, Richard.
> >
> > I always calculated it the same way as Keith...total cross sectional area
> of
> > the two pistons compared to the single piston, giving an advantage way
> less
> > than 26%.  Could you explain your math/logic to me?
> >
> > Thanks,
> >
> > Steve
> >
> > ----- Original Message -----
> > From: "Richard Tanimura" <richard at tanimuras.com>
> > To: "Keith Maddock" <Keith.Maddock at TRW.COM>; <s-car-list at audifans.com>
> > Sent: Monday, October 27, 2003 8:17 AM
> > Subject: RE: [s-cars] G60 brakes
> >
> >
> > > Huh??
> > >
> > > The front G60 calipers are 45mm and the rear G60 calipers are 36mm. You
> > > can't just add them.
> > >
> > > What we have to compare is 2 x 45mm with 2 x 56.8 mm (which you
> correctly
> > > calculated as the equivalent of 44 and 36). This means the Big Reds are
> > 26%
> > > larger than the G60's which is what I originally suspected.
> > >
> > > Rich
> > >
> > > -----Original Message-----
> > > From: Keith Maddock [mailto:Keith.Maddock at TRW.COM]
> > > Sent: den 27 oktober 2003 09:36
> > > To: s-car-list at audifans.com; richard at tanimuras.com
> > > Subject: Re: [s-cars] G60 brakes
> > >
> > >
> > > Rich,
> > >
> > > I should have worded my statement a little bit better.
> > >
> > > I said:
> > > "G60's have two pistons with the same effective size as an about 60mm
> > > piston."
> > >
> > > I should have said:
> > > "G60's have two pistons that together have the same effective size as
> one
> > > approx.  60mm piston."
> > >
> > > Looking at the data from Jimmy's site, it should be more accurate to say
> > > that the two pistons together (45mm & 36mm) are the same effective size
> as
> > a
> > > single 57.6mm piston.
> > > Perhaps they should have called it the G58 instead of the G60 !
> > >
> > > Regardless, to my original point, this is still larger than Big reds,
> with
> > > 44mm and 36mm pistons, which together  are the same effective size as a
> > > single 56.85mm piston.
> > >
> > > Thanks for pointing this out.
> > >
> > > Cheers,
> > > Keith
> > >
> > >
> > >
> > > Keith Maddock, TRW Automotive,  Koblenz, Germany
> > > Slip Control Systems, Systems Design, Traction Control
> > > +49 (0)261/ 895 2474    -   -   keith.maddock at trw.com
> > >
> > >
> > > >>> "Richard Tanimura" <richard at tanimuras.com> 21:43:52 25.10.2003 >>>
> > > Keith Maddock stated on this list that the G60 had 60mm pistons. I
> > stumbled
> > > over this information on
> > > http://www.urs4.com/technical/brakes/UrS4_brakes.html which indicates
> this
> > > might be incorrect.
> > >
> > > I am not in the least interested in being picky. Keith has helped me
> > > enormously in the past. But incase the data is important to someone, I
> > > suggest atleast that they double check the data.
> > >
> > > Rich
> > >
> > >
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