2-piece rotors, bolt + threaded hat, bolt+locknut or bolt+special nut?
 

What would be optimal type of attaching rotors to hats? I have wilwood non floating rotors.

First option is threaded hat and bolt:

http://img10.imageshack.us/img10/397...hreadedhat.jpg

Second option is bolt and all metal locknut

http://img6.imageshack.us/img6/634/boltandnut1.jpg

http://img805.imageshack.us/img805/891/boltandnut2.jpg

Third option is bolt and special stepped nut like bobbins.

http://img441.imageshack.us/img441/5...ltandtnut1.jpg

http://img856.imageshack.us/img856/4...ltandtnut2.jpg

The ideal would be to use a floating design with a specially designed floating nut or bobbin. Otherwise, go with a threaded hat like your top example. The only downside is possible damage to the hat with difficult to remove hardware (ie you strip the head and have to drill out the bolt). If this was a concern I would look at using a special step nut like the lower unit, but as you are using fixed rotors I'd save weight and thread the hats.

Elliptical offset nuts (all-metal-locknuts) are fantastic in some applications. For use on a brake rotor, however, I'd want to ensure aircraft-quality pieces, where the temperature and tensile strength are matched between bolt and nut. This is the only way to ensure they are truly reusable. For the cost, hassle and weight, just thread the hats.

Loctite 290 or 242 on the hardware, and use a belleville (domed) washer under the bolt head.

-Dave

Not to pry too deeply but are you working on a 2 piece rotor and brake setup for super's and/or standard bugs? I've been looking at off the shelf options using wilwood, 2 or 4 pot calipers and 2 piece 10.75" rotors.

As for brake rotor/hat assembly, the floating race setup is nice but not necessary for most applications. I'd go with the threaded hat or the stepped bobbin to keep things simpler.

My painter has Alcon floating brakes on factory made ex-Frank Biela race Audi 80, but he has also left two 330x32 fixed wilwood rotors and aluminum hats together with just bolts and all metal jet nuts from "super saloon" class 900kg Volvo PV with 250+hp, and they worked great at track. Car was race only, but not some 700hp track monster :lmao:

If you havent seen what car i am talking:

http://farm3.staticflickr.com/2657/3...fe8740d7_z.jpg

Audi is different, it has huge factory racing brakes from Alcon, with floating hats, barely fits to 18" center locking wheels. Whole car looks like almost stock old audi 80, but looks can be deceiving..carbon fibre fenders, hood, doors, nothing left from stock suspension etc.

http://www.pm-motorsport.fi/images/4.jpg

http://www.pm-motorsport.fi/images/1.jpg


I think i go with stepped nuts from cromoly and 12.9 capscrews, wonder if these materials like electric zinc coating?

Any chance you could provide me with more photos of the Audi? Cut my teeth in cars playing with lots and lots of Audi's...

-Dave

Yes i can have more pics, i see my painter almost weekly basis. When he bought it, there was stock chipped 5-cyl engine, but now he is getting built 1.8 turbo engine with 500+hp.

With that almost stock 5-cyl engine, he could not outrun Fiat Uno turbos at track :lmao::lmao:

As an S4 driver I am totally smitten with the audi... more deets?

As for these brakes... tap out the hat but make sure the hat depth is thick enough to handle it...