[s-cars] Big Reds Question?

[Richard Tanimura]

Angelo,

I think Linus is right on about the wheels. I think it is a little confusing
when he writes "This depends on .... which bracket, which caliper...".

I think what he means is that some people use the term "Big Red" loosely.
Porsche makes a number of calipers in different sizes which are large and
painted red. To me, a "Big Red" denotes a specific size. This size was used
on different model cars like the 928GTS, 965 and 993TT. Some have different
cylinder sizes. But outer dimensions of the caliper itself and the pads are
the same size.

The bracket's job is to position the caliper correctly in relation to the
rotor. For any given size caliper and rotor, the critical dimensions of the
bracket are fixed. So a correctly designed bracket made to fit the "Big Red"
to an A8L (323mmx30) should always fit wheels.

The "factory" solution is actually just a bracket (Audi PN 8A0 615 125 A).
It was designed to fit the RS2,928 S4, 944 TurboS, 968 M030 (Little Red)
caliper to a Porsche hub carrying a 314x32 Porsche rotor. The "factory"
never intended it to adapt the "Big Red" to an Audi hub carrying a 323x30
Audi rotor. I think that's why you need the 5 mm spacers (the rotor diameter
is 9 mm larger). I think the centerline of the rotor is also slightly
displaced relative to the caliper, but when you think of all the factors
that are different, it is amazing the thing works at all.

So if you want perfect centering and no spacers, you need a custom bracket
made for a specific caliper-rotor combination. ECS, Movit, BIRA and others
have developed such brackets.

Rich


-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com]On Behalf Of Linus Toy
Sent: den 28 januari 2004 01:40
To: 'Scott Munger'; 'Angelo Alexopoulos'; s-car-list at audifans.com
Subject: RE: [s-cars] Big Reds Question?


This depends on who's Big Red setup you use...which bracket, which caliper,
etc.
If you use the "factory" solution (RS2 bracket, 993tt caliper, A8L rotor)
you
will need to use a 5mm spacer with the forged urS 5-spoke (16x8) wheel.  The
interference is in the "shoulder" of the wheel, just past where the spokes
meet
the rim.  Interestingly, the 16" Avus wheel (16x7.5) will clear without a
spacer.


  _____
Linus Toy
Mercer Island, WA
linust at mindspring.com
  _____


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