Originally posted by Veronica
Bike stores tend to push you to ride a smaller bike. I'm nearly 5'5" and I ride a 54. Make sure you try something at least that big. I suspect that they'll push you towards a 50 or a 52. But try the larger size before you buy.
Just bear in mind that frame geometries differ, and that a 54 cm frame from one manufacturer can feel very different from a 54 cm frame from another manufacturer. Rivendell frames have lower bottom brackets and shallower (less vertical) seat tube angles than most other frames, the net result being that for a given frame size, the top tube on a Riv bike will be closer to the ground than the top tube for, say, a Trek. I'm 5'7" and I ride a 57cm Riv Romulus (like V. I was between 2 sizes, 55 and 57 but I opted for the larger size), but I imagine on a different bike I might take a smaller frame, simply on account of the different geometry, I'm not sure I would even be able to straddle the top tube of a 57cm Trek - not that I've actually tried.