Help me with some brake calculations plz

[DxC]

So, there's a lot of drama regarding these brake calipers I recently bought ...

http://www.audizine.com/forum/showthread.php?p=2522000

http://www.audizine.com/forum/showthread.php?t=213343

if you feel like reading it ... but cliffnotes: they are custom made st40 calipers for a different car (not audis) but st40 blanks are all the same, just these have 32mm and 36mm piston sizes, instead of 32mm and 38mm.

ill eventually need to machine the caliper mounting bracket, but ill cross that bridge when i get there (and when i have access to a 5axis cnc machine)

can someone just chime in on these calculations? also does anyone know what the calculation for finding brake bias? assuming everything except piston sizes stays constant.

[RolledMySTi]

My brain hurts just looking at that.

[DxC]

its a simple area calculation ...

though i just realized my values for radius is actually the diameter ... so i need to re-run the #s .....

but is that right? i feel like i should be using pi*(r2-r1)^2 because that's the actual contact area ...

[exorcet]

wouldn't pressure play as much, if not more of a factor than area?

[DxC]

pressure matters too obviously ... the formula for force is Force = Pressure*Area ... but the pressure is pretty much given from the master cylinder. the area is the piston area ... so if pressure stays constant, and the area increases, the braking force increases