I am a 5 '0" tall female and have been riding a Diamond Back tg road bike for the the past 20 years. I am fit and able to cycle 40-50 mile rides well. I have spinal stenosis in my neck and am looking for a lighter (probably full carbon) new women's bike that will not require hyperextending my neck. I have tried 2007 Specialized Ruby Expert 44 cm and 48 cm, as well as 2007 Cannondale Synapse Feminine 2 or 3, 47 cm frame size. My trunk position is closer to 45 degrees on the 44 cm frame, which in general feels more comfortable. However, after trying all three bikes, I have felt some discomfort in my neck and back. Perhaps this is just due to riding in a different position, although these were only test rides. Since I don't know which frame size contributed to it, I plan to try one bike each day and see the results! The bike shops have been helpful, but I am still seeking more info so I can get a bike that I will ride for a long time. Any opinions on the bikes above, suggestions on other bike manufacturers that meet my needs, as well as on how to determine if the 44 cm frame is too small or not would be greatly appreciated! Susan