My point at the start of the thread though was that if all you do is increase the size of the slave pistons, while still using a standard maggy lever, the pads would physically move a smaller distance for a given lever pull than when using normal maggy slaves. That would mean you'd get more powerful braking when the pads touch the rim but to get them to touch in the first place you'd have to run the pads really close to the rim itself and end up being screwed with a slight buckle. And yeah, as Adam(s?) says, air is just a fluid and so pneumatics must act in exactly the same way (in a closed system) as oil/water/whatever since they are both effectively incompressible under normal atmospheric conditions. (exhales sharply through nose)