Also, increasing the area of the piston intensifies the force behind it using the formula F=PXA where F is braking force applied to the rotor, P is the pressure of the fluid behind the piston and A is the area in which the fluid is being applied to.

A 1cm2 with 100psi applied = 100lbs of force
A 2cm2 with 50psi applied = 100lbs of force

Increasing the size of your piston will in turn increase how deep your teeth dig into the steering wheel.