BobA
Member
A 18 inch frame will fit someone with a 33 inch inseam. The only way to really tell is to ride it. You want to adjust the seat to the right height and then look at the seat post to see if the minimum insertion height is showing or not. You can buy longer seat posts if the bike feels good.
http://www.coloradocyclist.com/bikefit
http://www.coloradocyclist.com/bikefit