Bell/Hat thickness for a 2 piece Rotor setup.

Hi Guys,

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

Closest thing I could find to a drawing of an existing design via a quick google search:
http://www.gt40s.com/forum/gt40-tech-chassis-brakes-tires-wheels/25570-rcr-rotor-hat-dimensions.html

I can't tell if that is 6mm or 8mm, wish it was a bit higher res.

My feeling is 10mm is fine.

.25" for the aluminum hats is pretty common for the Wilwoods...

http://www.wilwood.com/Hats/HatList.aspx

Thanks Guys,

My biggest concern was any tortional twist that might be caused by centrifugal force when cornering but it seems that I'm worrying unnecessarily.

Cheers
Nick

That section is sandwiched between the hub and wheel. The outer section is bolted to a fairly stiff steel brake rotor. Not much worry about twisting or any other sort of movement in my opinion...

one slight difference, my rotor hat will not be sandwiched between the wheel and the hub but instead bolted to the rear of the hub. but again I don't think it'll make that much difference...

dirtbike said:

one slight difference, my rotor hat will not be sandwiched between the wheel and the hub but instead bolted to the rear of the hub.

Click to expand...

whoa. Some kind of custom hub? Is this just because of how the caliper offset works out? That changes things a bit I think. The mounting at the hub has a lot more torque on it. In the traditional arrangement there is no shear load on the wheel studs or load on the mounting holes themselves at all, the whole hat is supported by the clamp load...

dirtbike said:

one slight difference, my rotor hat will not be sandwiched between the wheel and the hub but instead bolted to the rear of the hub. but again I don't think it'll make that much difference...

Click to expand...

On the early 911/930's, the rotor was bolted to the back side of the hub on the fronts.

http://www.turbosport.co.uk/showthr...S2000-X-Pack&p=1683667&viewfull=1#post1683667

Here is a pic of the what I'm planning but I'm using different hardware.
Brembo 4 pot Calipers, Wilwood Rotors, home made bells and after market Aluminium Hubs (same as those pictured)

Mueller said:

On the early 911/930's, the rotor was bolted to the back side of the hub on the fronts.

Click to expand...

And my lowly Escorts original iron 1 piece rotor and iron hub where bolted up in this same way
Kind regards
Nick

dirtbike said:

http://www.turbosport.co.uk/showthr...S2000-X-Pack&p=1683667&viewfull=1#post1683667

Here is a pic of the what I'm planning but I'm using different hardware.
Brembo 4 pot Calipers, Wilwood Rotors, home made bells and after market Aluminium Hubs (same as those pictured)



And my lowly Escorts original iron 1 piece rotor and iron hub where bolted up in this same way
Kind regards
Nick

Click to expand...

Neat cars on that site !!

I did the design and drawings for these below, they allow vented 911 rotors to be used with Porsche 914 4 lug rims (not everyone wants 5 lug) ... most use 911 dual piston calipers or Volvo 242 4 piston calipers !!!

I know these are one piece rotors, but 2 piece are done as well that mount this way....for mine, I used Wilwood hats with a .30" thickness, and a .50" offset if I remember correctly