Retract works on the annulus, not the bore: the rod\’s cross-section is missing from the piston face. A 100 mm bore with a 50 mm rod gives 75% of the force on the way back — and 133% of the speed for the same pump flow.
Force is pressure times area and speed is flow divided by area, so the same missing area that costs force hands back exactly that much speed. Force × speed is pressure × flow in either direction: a cylinder trades one for the other precisely and never creates power. Pick the rod at bore ÷ √2 and the annulus is exactly half the bore — the classic 2:1 cylinder, half the force back, double the speed, chosen deliberately rather than by accident.
It says nothing about which direction is the working one — plenty of machines pull rather than push, and are sized on the annulus from the start. And a double-rod cylinder has the same area both ends, so the asymmetry vanishes entirely.
Estimate with the rule, then check it against the calculator that models it properly.
Open Hydraulic Force Calculator →Retract works on the annulus, not the bore: the rod\’s cross-section is missing from the piston face. A 100 mm bore with a 50 mm rod gives 75% of the force on the way back — and 133% of the speed for the same pump flow. Force is pressure times area and speed is flow divided by area, so the same missing area that costs force hands back exactly that much speed.