[Chris Fultz]

A 2.5" cylinder from Bimba has a 0.625 pushrod. Assuming you will retract the rod to pull your robot up, we need to subtract that area to determine the capability.

2.5" diameter, less the .625 rod, gives an area of 4.6 square inches. 24 inch length = 110 cubic inches of volume. This cylinder has 275 pounds of force to lift your robot.

2" diameter, less the .625 rod, gives an area of 2.83 square inches. 24 inch length = 68 cubic inches of volume. This cylinder has 170 pounds of force to lift your robot.

The 2.5" cylinder has 160% of the volume of the 2" cylinder, so it will take about 160% of the time, assuming you have the available volume of stored air.

If your robot weights 120 pounds, +12 for battery and 15 for bumpers, you are close to 150 pounds that you need to lift. Remember that you will also have some friction to overcome if the robot is sliding up the front of the tower.