Originally Posted by
fietsbob
Physically a high volume Pump cylinder would be larger diameter , to move more air, per stroke.
but a high pressure would be a longer tube , so the amount of air compressed with a long stroke
the length of stroke is your compression ratio. and would not need to be so large a tube diameter..
The two in question is the same length, only a smaller diameter for the high pressure one, which amounts to the same: Less air per "length of stroke", but a tad easier to push at higher pressure than the high volume one.