Pedal ratio, the force reaching the master cylinder, and the line pressure it makes. Handy when swapping to manual brakes, changing master cylinders or building a custom pedal.
The pedal is a lever that multiplies your foot's force. A smaller master cylinder bore makes more pressure from the same force but moves less fluid, so the pedal travels farther. Bigger bores do the opposite.
Measure the pedal distances with the pedal at rest, from the pivot bolt center to the center of the pad and to the pushrod pin.