Summary of Equations:

(for ease and consistency try and use meters and kg)

1.

stopping force = weight of car * longitudal coefficient of friction of tires

2.

Stopping Force = pedal force * brake pad coefficient of friction * mechanical force ratio * (1/radius of the tire) * brake rotor effective radius

.....solve for mechanical force ratio

3.

Front Force = weight front + total weight * tire friction * height of CG * (1/wheel base)

4.

Rear Force = weight rear - total weight * tire friction * height of CG * (1/wheel base)

5.

% front = Front Force/Stopping Force

6.

% Rear = Rear Force/Stopping Force

7.

mechanical force ratio front = mechanical force ratio * %front

mechanical force ratio rear = mechanical force ratio * %rear

8.

Take that ratio and divide it by the pedal ratio.

This is the ratio of mastercylinder bore area and caliper piston bore area.

So say a 4:1 then for a 30cm^2 caliper piston you want a 7.5cm^2 MC or ~28mm bore MC.