question about 993tt rotors

Kenneth Keith auditude at
Mon Apr 24 17:16:07 EDT 2006


Some of you may be running brakes using 993tt rotor rings and custom
hats, and able to help with my question.  I have a Billzcat1 Turn 9
setup for my 200q20v, which has custom hats and brackets to mount
996tt "big bloc" calipers and 993tt rotor rings, and I've got a
question about the hardware that holds the rings to the hats, which
consist of "t-lock" fasteners and bolts.  I bought the kit with unused
rotors from a lister and am sorting things out to install them.

The t-lock fasteners (sort of a sleeved nut) that attaches the rotor
rings to the factory hats (which need to be removed and replaced with
the custom ones, re-using the hardware) are different from left to
right.  These t-lock fasteners have an internally threaded tube that
runs through both hat and rotor, and the bolt goes through that from

One set/side (can't remember left or right) has longer fasteners that
bottom out against the bolt before the rotors are clamped tightly
against the hats, leaving the rotor able to float away from the hat
slightly, and the other set/side has a stepped fastener that is quite
a bit shorter and when bolted up will put the hat in tight contact
with the rotor ring with no play.

The diameter of the holes in one rotor is about 5.0mm and the other is
5.5mm, as far as I can tell.  Both t-lock fasteners are 5.5mm towad
the "head," as are the slots in the billzcat1 hats, and the "shorter"
set of t-locks has stepped down to go into the 5.0mm holes.

I think the 5.5mm sections of the shorter ones might be the correct
length to bolt up to the hat leaving some float, but cinch up against
the rotor firmly, while the other t-locks are different and would
leave both rotor and hat able to potentially float along the whole
fastener (instead of just on the thicker part that goes inside the
hat, being solidly attached to the thinner part between the bolt and
"shoulder" created by the 5.5mm-to-5.0mm reduction.  I don't think
more words will help in describing this, so that's it for now. =)

In addition to this difference between left and right rotors, I also
found that one of the rotors had a thin black gasket between the
factor hat and rotor ring, but the other side didn't have any such
gasket.  The gasket is way thinner than the difference in t-lock
length (depth really, as the overall length of the fasteners are the
same, but the "shorter" ones have a much thicker "head" area).

I haven't gotten a chance to take pics yet, but I will do that.  My
basic question is whether there should be a difference between how the
left and right rotors are attached to the hats.  If one is better than
the other, such as the shorter ones that bolt up tighter, then should
I shorten the longer ones?  Right now, if I bolt it all up without
worrying about it, one rotor/hat combo is completely tight and the
other has play where the fasteners can slide back and forth (or the
hat pulled away from the rotor slightly).



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