Technical master cylinder size?

Not your typical question about m/c bore etc. Does the MC care about the weight of the vehicle? I understand hydraulics fairly well and to my knowledge the weight should not matter because it just pushes the fluid to clamp calipers/drums or whatever. The psi of the MC is governed be the bore/stroke the clamp load is the rotor size pad suface area which has no Bering on mc pressure. Am I correct or is my mind wondering off.

Kris,

 

I think you are generally correct in your reasoning. Things you may also have thought of is that the volume of the MC (function of bore/stroke) needs to be sufficient for the volume of the calipers and/or wheel cylinders. Also, the diameter of the rotors/drums is a factor in braking capacity. Having said that, I think your basic premise is on track.

 

Since you need the brakes to apply more stopping force with a heavier car, you want the calipers to clamp tighter, so you need more presser than with a lighter car.

The smaller the MC bore, the more pressure you get for the same pedal force.

The MC is just a chunk of metal, it doesn't care about anything. But the driver might be able to stop a heavier car more easily if it has a smaller bore MC. I made that change to my 55, it's more pleasant to drive now.

 

Does a larger diameter tire make a car harder to stop, rolling inertia?

 

There's a little more rolling inertia, but it also decreases the leverage that the brakes have.

 

The weight should not make any difference directly. It may indirectly, if it affects the size of the brakes you use, the size of the wheel cylinders or calipers, the pressure you need.