Anyone got any experience with speccing master cylinder size?

[massiveCoRbyn]

Does anyone have access to a good calculator for this, or able to give me some guidance?

A couple of drives in my car have revealed that the brake pedal is pretty long. I need to bed the pads in, so the brakes aren't brilliant obviously, but there seems to be a lot of pedal travel regardless. Pretty certain I have no air in the system, so I am wondering if I need to change a master cylinder.

Am running a 0.75" front, 0.875" rear, four pot calipers on 325mm discs up front (2x 36mm, 2x 40mm piston), 260mm rears with twin piston calipers.

In "rule of thumb" land, a 0.75" front cylinder seems about right, but I'd like a harder pedal really.

Any thoughts?

 

[JamesBryan]

This any good?

https://www.joesracing.com/rt-4172-master-cylinder-math.html

 

[Usr117063]

@massivewangers what setup are you running? I have ap racing mcs to go in with a Tilton, I want a hard pedal as well but don’t know what to expect as never driven with one before.

 

[bozothenutter]

i think you need the diameter of the brake pistons (or surface area actually)
add them up, and the decide which ratio you want (ie same surface is 1:1, 2:1 etc first in this example is calipers, second mbc)

what calipers are they?
if from another car, you could use that as a starting point and go UP from there.