mark kibort

Racingbrakes.com have a great product. i got a version that wasnt quite as evolved as the current product, but the metalurgy proved to be MUCH better than stock zimmerman or porsche OE.

I got an entire season out of the rotors, when normally, i would have to replace them after 3 weekends.

the older versions had a sub par venting design, since has been changed to one that looks to be better than what brembo supplies on their custom rotor.

the pictures below are the brembo with the holes, the original RB.com rotors and the black ones which are painted new versions. (the pain wears off in about a mile of dragging your brakes on and off )

i dont particularly like the hats as they are not hub centric and you can see the centering screws are taking some forces to the hat holes .

Ill have to find a way to make an adapter centering ring somehow.

RacingBrake

Hi Mark,

Thanks for sharing your experience on RB replacement rotor rings. As we discussed I can't emphasize enough for the importance of rotor hat and how they are attached to the disc.

Our rings are made to replace Brembo 13" (332x32) rotor rings so it's assume a customer would bolt these rings to the original hats w/o any issue or concern.

However to the benefit of Porsche racing community I like to share with you for a proper hat design. Essentially we want to keep the disc slides out and in during heat cycles, so the disc mounting tabs have oblong slots while the hat has round hole.

When a two piece rotor is properly assembled together, all nuts s/b tightly against the hardware shoulder with as very little twist angle and all mounting points should be all even, this will assure the disc is assembled "concentrically" to the hat.



View of the hardware in hat section, the nut sit inside the hat round mounting hole snugly without a play.


Disc mounting tab has oblong hole, and the nut sits towards outer edge of the hole.



When it refers to PCD, we rather to call it out where the bolt center is than the center diameter of the oblong hole


So when the disc is heated up it expands outward, and the bolt ends up positioned around the center of the oblong hole. These oblong holes allow the disc to extend & shrink without stressing the rotor hat, thus keep the disc/rotor from warping and cracking.

I have seen some two piece rotors simply bolt together with round holes in hat and "disc" which severs no functionality of this heat stress and are destined to failure.

Inside the disc is our patented "Convergent Vanes" for a more efficient cooling than conventional van design as detailed in this thread.

https://rennlist.com/forums/991-gt3-...l#post13069941





Learn more about our simple and easy hardware with self-lock feature etc.

http://www.racingbrake.com/product-p/fk5-10.htm

RacingBrake

Here is a detail view of RB hardware interacts between the hat and dsic, with a photo (on left corner) showing the actual disc movement during heat cycles.

Bolts are certified by RB with 10.9 grade.

puyi

Interesting

I have been on RB website. I wonder if there is any application for 928 with rotors less than 320 mm and 32 mm thickness?

Let me know, I have a restricted rule in saloon car championship and also, I like the idea of independant hat from the rotor.

The "ideal" would be 313 x 32 with original pads and very little change in calipers mount.

Thanks for the information

puyi

RacingBrake

Yes we do.

320x32 is the size as Mitsubishi EVO (03-06) that OE is one piece and we offered two piece upgrade which is one of our top sellers other than Corvette Z06 track enthusiasts.

We have discs for both surface mount and center mount.

Surface mount:
http://www.racingbrake.com/Two-Piece...O-8-p/2216.htm

Center mount:
http://www.racingbrake.com/Two-piece...ONT-p/2018.htm

Both (discs) are in stock, if you can let's know more about your requirement we can take a look at it.

mark kibort

i never would have imagined the advantages of their metalurgy.. amazing, even vs the GTS 322mm rotor , PORSCHE OE, it lasted all season with little cracking, and i think the their new design is even better

you need the 304mm rotor to keep with in the stock S4 dim?

the real question is if RB.com makes the hat with the C2 turbo hat or (965T) or
GTS (322mm rotor) and then has a smaller diameter rotor ring to match rules requirements ?

Do you have a hat for him or does he need to have that made?
one of the problems i have with the hat i have, is its not hub concentric, which seems odd considering how important the centering of the rotor is. but the centering screws seem to work and not break off, so i guess its ok.

mark kibort

Looks like ill be able to use the 348mm rotors next year with the existing calipers. that will be near 14" diameter and all i need to do is find .35" longer caliper mounting bolts?? any help here??

and make the spacers i have .35" thicker or should i make a bar that incorporates both holes for a spacer or does it matter?

RacingBrake

Here are some real two piece rotors just assembled for shipment.





These are of center mount design, and you can see how tight and uniform of these hardware nuts against the shoulder. Each rotor hat is lazed with P/N for positive identification of application and their respective replacement rotor rings.

H704-22A is for Mazda RX8 front RB BBK (332x26mm)
H704-16 is for Mazda RX8 rear two piece stock upgrade (303x22mm)

RacingBrake

Since you asked about the hat so I like to share with you how we make our rotor hats. We have tooled up for forging blanks in 7", 8", 9" and 10" with various height (e.g. rear drum hats are deeper than front hats)

Making our own forging blank can assure us for stable supply, consistent quality and quick turn around.

Since our rotor hats are machine from forged aluminum so they are in general about 25% better in strength and rigidity than those cut from billet, as you can see from the Brinell hardness test indentation (our 121) comparing to standard aluminum alloy from extrusion (billet) @95. Most OE two piece rotor hats (incl BMW, Porsche etc. supplied by Brembo) are as low as 65 (see pic below) as they are "casted".

So making a new hat for us is quick and easy, provided they are not custom application with rare movement.

Various forging blanks


Blank with forging grains and hardness test



Stock shelf


OE rotor hat and disc hardness test


As to these older Porsche applications, we have to learn more from you.

mark kibort

might be easiest to send out a stock rotor to you to match the ID and the offset.
I could see if there is a bunch of 928'ers that would want the custom hat. in the end, it would be WELL worth it to dump the stock rotors and get something that looks and wears much better!

great stuff... you guys are doing it right!

RacingBrake

There are several different sizes of OE rotors



Source: http://www.928motorsports.com/parts/gt1_brake_kit.php

So can you be more specific if you just need to convert OE 1pc to two piece rotors (and in what size 304mm+?) or are you looking for BBK, and if BBK what rotor size (relating to your wheel size) you have or like to have.

For example your replacement ring is 332mm but it wasn't in the rotor size chart above?.

We already have 928 front and rear spindles in house, and a better rotor development would base on the actual mount of caliper than just a rotor sample.

atb

Any estimate on what the price for the 928 hat would be?

I would definitely by interested. I think others would be as well depending on the price point.

AO

Also interested in the 304mm size.

RacingBrake

What size of rotor.

atb

Personally I'd be interested in the 322 or 355mm.

I was hoping that you could produce one sized hat, and then the purchaser could choose his rotor size. Does each rotor size have to have a hat made specific to the rotor's diameter?