What size shoe would fit a 5'4" person? Picking a bicycle frame is at least that difficult to guess. Body porportions vary and bicycle measurements vary.

Some bikes are measured in inches, some in centimeters, some as small, medium and large. There are different styles of bikes which would require different sizes for the same rider. Finally, even once you get past all of the above, the bicycle manufacturers don't all measure things in exactly the same way.

If I were buying shoes, I'd want to try them on. The same is true with bikes.