I am 6' and wife is 4'10.5!! We started on a Med/Small Trek T1000 and now ride a Co Motion Supremo. We did add a "special piece" for lack of a better term from House of Tandems to make her bars higher so she is more comfortable because of her short torso and arms. I wish posting pics on here was easier. Message me your cell number and I will happily send some to you of what we have done. We also put on shorter cranks. She has to ride with the seatpost all the way down. We put on a cobble gobbler seat post also because it's much shorter than a Thudbuster.