Here are the specs I have for the rotor and hat. These are updated slightly from what I built as I had one small error, the bolt circle was a bit too small and I had some interference between the bolt heads and the hub on five of the bolts. I had to grind the bolt heads flat and enlarge those 5 holes slightly to get the bolts to drop in. This version should have enough clearance there and the hat is .25" larger, so .125" bigger radius which will give enough clearance for the bolts but still clear the caliper and pads.

The dimensions are all on the rotor sheet to fill in the Coleman PDF custom rotor spec. sheet, but I would encourage everyone to double check my dimensions :-)

Flo, you can see here that the rotor diameter is 285mm (11.2") which is just slightly larger than the 282mm Carrera/SC rotor. I wanted to make sure there was no pad overhang and be able to move the caliper a bit more outward axially to clear the rotor hats on the inside. Coleman Racing made the rotors, Mittler Brothers made my hats. If I were to have hats made again I'd have my local guy (Jay of Jay's machine shop here in San Jose) make them, he quoted me $75 each which is a great price. Mittler Brothers were great though, easy to work with and relatively quick for a one-off very small job.

My Coleman contact is a gentleman named Glenn Myers, very helpful and great to deal with.

http://forums.pelicanparts.com/uploa...1597186249.jpg

This sheet still calls out a 0.25" thick hat, as mentioned above I would probably go with a .3125" (5/16) thickness, readily available stock and move the rotor inward so the caliper can also be moved in away from the wheel spokes without having to add wheel spacers.

http://forums.pelicanparts.com/uploa...1597186249.jpg

This has definitively been on my to-do list since I got my 911, thanks for the info and write up I hope to follow your steps soon

Here is the Coleman rotor setup sheet. The above post has all of the proper dimensions. They have several different rotor blanks to use as starting point, can all be found on their web site.

http://forums.pelicanparts.com/uploa...1597245471.GIF

Grabbed this photo from another thread on the topic, shows where the "nubs" need to be ground down in the caliper throats to clear the larger rotors. These mods are required for both the front and rear rotors

http://forums.pelicanparts.com/uploa...1597425437.jpg


Finished result. You can see here where the four nubs have been ground off on the outer portions of the caliper. You also need to grind the screws that hold the pad retainer plates on, and the four nubs on the inside of the calipers as well.
http://forums.pelicanparts.com/uploa...1597425437.JPG

Did the custom rotor hat come from Coleman or did you make it? Any chance that you have a Stp file?

Thanks

David

I had a company called Mittler Brother's make them for me. They have a similar product but different bolt hole locations etc..., so I just gave them a call and they were happy to machine them for me. Any local machine shop should be able to knock them out in a couple of hours.

And no, sorry, I don't have any cad files, just Powerpoint from which I exported the attached GIF.

Bill

OK, thanks, I will have a designer @ work draw them up for me. Why am I seeing 4 piston and 2 piston rear 964 calipers? Also can someone post a link to the modifications that are necessary on the rear calipers? 3.5 inch to 3.0 inch

My designer drew these up for me using Bill's diagram.
I asked my water jet guy to make me 2 at .25 and 2 at .3125.
So I have two extras if someone is interested in them send me a PM.

To clarify these are $100 shipped (CUSA)

http://forums.pelicanparts.com/uploa...1597871311.jpg

I just wanted to share my experience with Coleman rotors. I had Coleman make two sets of rotor rings for my 993TT brakes for use on my track car and both sets warped in two laps. Apparently, they use a very low grade of steel, which does not like track temperatures. This is a common Coleman issue that is well documented on Rennlist's 993 forum. For street use the Coleman rotors should be fine.

I'm going to tweek the design and recommend M6 fasteners around the perimeter. My reason is two fold;

packaging is very tight and the m8 is overkill. The 5 M8 bolts used to attach the adapter to the hub collectively generate 82 Kn of clamp load. The 10 M6 bolts that I'm suggesting can collectively generate 90 Kn of clamp load. Furthermore I'm pretty sure that the original design also uses M6. Coleman can make the holes smaller.

On another note I have one more pair of 1/4 adapters and one pair of 5/16 adapters.

David

Are the different hat offsets for different calipers or?

There is really one one hat design here. The goal is an economic means of putting bigger calipers and rotors on our cars.

Oh. I get it. The spec: hat to rotor mounting holes.

1/4" (.25") holes x 10
vs
5/16" (.3125") holes x 5

Both flanges are 1/4" thick.

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Correction: Harpo had/has two sets of rotor hats. One set of hats are 1/4" thick, another set are 5/16" thick. Both are designed to fit a rotor with (10) x 1/4" mounting holes.