Rize uses the Suntour seat post, and it is just about the tallest default height on the market at about 4" unloaded. If you are a shorter rider than 5'8", I'd skip the seat post until you get the bike, and then see how much room you have to work with based on your actual inseam. Some other options like the Redshift shockstop only require 3" or so, and the Kane Creek eesilk only needs 2.75". Seat thickness will also factor in, as you could run a larger seatpost if you were comfortable with a slimmer saddle. Or if height is a real premium, consider a seat with integrated springs and skip the post altogether...