Hi Eilidh, I don't ride a Safire, but I do ride an Era Expert and I think that the geometry is pretty similar, as I test rode the era and the Safire last summer, if I remember the big difference was the Safire had more travel. Incidentially I love love love my Era, and have been riding it around Sedona lately. I'm just under 5'8 and have a medium, fits like a glove. My legs are a little bit long, but not much. Hope that helps!
"I think it has done more to emancipate women than anything else in the world. It gives women a feeling of freedom and self-reliance. I stand and rejoice every time I see a woman ride by on a wheel...the picture of free, untrammeled womanhood." Susan B Anthony