2 piece Brake/Bell setup questions

[dirtbike]

Hi,

This is my first post here...
I'm 75% of the way through a major build of my car (Mk1 Escort) and I'm currently in the process of building my front brakes.

I'm using Brembo 4 pot calipers from a Fiat Turbo Coupe (same as Peugeot 406 coupe, Mk1 RS Focus.
I'm using a 2 piece disc/bell setup, the discs that I'm using are 310mm Wilwood Ultralite 32 Vane and the bells will be home made. My question is how thick should I make the bell...

There will be 0 offset from the disc to the bell so essentially the disc will be bolted to a flat aluminium plate. I intend using a 1/2" plate of 6082 aluminium, taking off the 2.7mm to use as a locating shoulder for the disc leaving 10mm thickness to handle any tortional forces (which should be fairly minimal) my only concern is whether that is enough?
The other option is to use 5/8" aluminium plate and machine a shoulder into that to locate the disc and take the overall thickness of the bell to 13mm opposed to 10mm with the 1/2" plate.

What are your thoughts?
Kind regards
Nick

[Mr2Mike]

Rally Design suggest the bell should have a thickness of no less than 8mm.

[bertelli_1]

Aluminium???

[PhillipM]

It really does depend on your design, the radii you can put in when machining it and the material itself - my bells are 7mm thick for example - 6082T6 - but have large radii anywhere there was a stress concentration and are thicker in the areas where they drive the disc lugs.

[dirtbike]

I should also add that the rotor hat/bell is not sandwiched between the hub and the wheel but bolted to the rear of the hub much like the standard setup.

[RichB]

I have bells and rotors on my TVR and to counter warping due to heat expansnsion they used floating bolts (whatever they are) I understand the concept but not the details...