What is your inseam measurement? At 4' 9" I'd guess you probably have an inseam similar to mine. I'm 5' but have short legs for my height and have an inseam of 25". If your inseam is the same as mine, it may be difficult to find a diamond frame road bike that gives you enough clearance to stand over. Unless you get one with 24" or 20" wheels. There are a number of youth road bikes that use 24" wheels, and various folders and mini velos on 20" wheels. Otherwise, you might look for a small mixte or step-through frame bike.