Not sure how helpful this is, but my wife @ 5' 1" has the Stunner LT Sm (20" wheel) and has to have the seat at it's lowest. I put a Thudbuster ST suspension seat stem on, but had to take it off because the additional 3" or so was too much for her. So I'm thinking the X 24" may be pushing it for a 5' 4", but it also depends on inseam length.