WINDSOR CITY BIKE SIZING
Mens 51cm fits most riders from 5' to 5'9
Mens 56cm fits most riders from 5'9 to 6'2"
Ladies 46cm fits most ladies from 4'10" to 5'7"
Ladies 49cm fits most from 5'7" to 5'10"

If you are between sizes:
choose the smaller if one has shorter torso/arms
or the larger for longer arms/torsos.